Fusions to blend the following metal combinations were made on plaster tablets to avoid introducing contaminates, and to see if Tellurium can be found using microchems with only 3 precipitating reagents. It is also hoped that these microchems will detect all the elements listed.

1. Te,
2. Pb + Te,
3. Pb + SbS + Bi +Te,
4. Pb + SbS + Bi + Te + Ag
5. Pb + SbS + Te
6. Ag + Te
7. Te + S

The primary reason for using plaster tablets to melt the various metals upon is to avoid unwanted and/or unknown contaminations that other surfaces might introduce. Plus, these white tablets are cheap to make, clean, easily handled and cool quickly.

Another reason for these tests is to help determine the probability that some unknown minerals being examined are contaminated within a matrix that may include tellurium with one or more of the mentioned metals/minerals.

Antimony sulphide was used in these tests instead of pure antimony metal to help introduce sulphur into these other metals that were fused together. Elemental sulphur was also combined with Te to see if a TeS could be generated by simple fusion.

There are hundreds to thousands of possible combinations that can be made. Trouble is that conducting such tests is a time consuming study.

The typical fire assays will not obtain this kind of information. One can spend several thousands of dollars utilizing any number of instruments to get some idea of what may be present in rock of interest. But, because of limited financial resources this type of comparison study is a good alternative which allows duplication.

10x – Tellurium melted on plaster tablet.
Don’t know, yet, what the white spheroid is.
The dark area on plaster tablet is a Te sublimate (oxide) generated from the hot map gas torch flame, which was applied at the lowest possible setting without being extinguished. Obviously, this visible physical fact indicates that Te is very volatile.

50x – A magnified view of the preceding image.
This photo has shadow effects making it appear brownish.The original tellurium is very brittle and crystalline, which was melted to obtain this spheroid on the plaster tablet.
The crystal grain boundaries are easily recognized.
Although this Te metal is 999+% purity and both a high and low heat range was used a molten round shinny bead was not obtainable with the Mapp gas hand held torch.

50x – The Te is in a solution of 1 drop nitric acid and 2 drops distilled water that has become supersaturated after about ½ hour.
The metal spheroid is almost covered with a white non-descriptive mass coating with some snow white crystals radiating outwards.

50x – The saturated solution, almost dry covers the whole area of solution with this white flock that is resting on glass slide.
No precipitant forms with either NaCl or K2Cr2O7.
A toothpick assay of the solution produced barely a glimpse of any metal and not enough for the microscope camera to focus clearly upon. Most of the toothpick had a white residue where burnt and after repeated ignitions formed an orange-yellow grunge.
Concentrated HCl has little effect on the Te metal; but when exposed to heat the HCl seems to cause widespread vaporization leaving visible traces of white tiny crystals all over the glass slide.
Aqua-Regia vigorously attacks this high purity Te, creating a yellow solution as shown in the next image.

50x – The Te in act of digestion in Aqua Regia solution.
The yellowish solution is flowing rapidly all around the Te metal in the form of air bubbles.
Placed a toothpick tip in this A-R solution and ignited. There was a beautiful blue colored flame and a really odd unidentifiable odor.

50x – Toothpick tip that was ignited leaving only a white residue, which would not reduce to metal no matter how many times ignited in the oxidizing or reducing part of cigarette lighter flame.
During ignition of toothpick tip there is that odd unpleasant odor.

10x – The dried Aqua-Regia (A-R) solution illustrating the Tellurium that was in suspension and is now a dry white mass that has a slight/faint amount of yellow color.
Added 3 drops of concentrated HCl to this white dry mass and heated to drive off all nitrates from the nitric acid used to make the A-R solution. Repeated this step 3 more times to be assured that all the nitrates were gone. Failure to get rid of the nitrates will cause the Iodine in KI to reduce and thus making a mess of the microchem, as well as losing an hour or two and the time to repeat the test.

40x – After driving off the nitrates from the A-R solution a couple small crystals of KI was placed in the solution. There was this immediate black precipitate, which can only be one of two items – either reduced iodine or Te.
According to webelements.com all the iodides of Te (TeI, Te4I4 & [TeI4]4 are black), although Te2I is silvery gray, which may be the gray-white precipitant found under the section Pb+Te.

K2Cr2O7 (Potassium dichromate) and NaCl (table salt with any Iodine) do not cause a precipitation under this condition.

2… Pb + Te

10x – The fused Pb and Te on plaster tablet.
It was difficult to melt these two metals together and prolonged heat was required and not all of the two metals alloyed.
The plaster table is flat and about ½ inch thick and where the metals are is a carved-out crater to contain the metals from blowing away from the force of the torch flame.

20x – A piece of the fused Pb & Te.
When removing the partially fused metal fragment from the plaster tablet portions broke and has the appearance of being partially hollow.. Perhaps, gas formed within the molten metal causing a cavity just under the surface skin.

20x – The PbTe metal bead in a solution of 1 drop nitric drop and 2 water drops with a little heat applied to underside of glass slide.
No further heat was required, for it continued to digest.
The remaining undigested bead was removed from solution and slide for later use.
There was no pearly opaque gangue on top or sides of button as indicated in this image when this metal fragment was removed from slide, indicating that it had dissolved.
When examining internet web images of tellurides from different parts of the world it is rather common to see this pearl white with a slight green color coating portions of rocks. Whether or not this coating is some form of Te I do not know, but is too common to be merely coincidence.

50x – In the supersaturated PbTe nitric acid solution these white transparent to translucent crystals have formed around the perimeter of solution.

50x – Placed 3 NaCl in the Pb + Te nitric acid solution, which immediately formed the precipitate surrounding the sodium chloride crystals.
No typical PbCl feathers grew from these needle like precipitants. Is this because Te is interfering or too strong of acid solution? Questions like these require answers, which, for me can only be found with more tests..

50x – A single crystal of potassium dichromate (K2Cr2O7) added to the solution slowly produced this contaminated lead chromate precipitant, which is best viewed growing on edge of chromate crystal.
The color is just a tad too red, should be a little more orange for Pb.
The chromate crystal is hollowed-out leaving the cubic original structure.

50x – This tooth pick was dipped into the solution of PbTe and nitric acid prior to any precipitating reagents and was then ignited. Some small metal beads formed (likely, but not sure if a combination of Lead & Tellurium).
These molten metals would also volatize before I could capture a discernable image. The crude (spheroids) that formed are not metal but orange to white globules.
The only meta with a dimplel this image shows is at about the 9 o’clock position.

3… Pb + SbS + Bi +Te

10x – Image is illustrating these 4 metals fused on a plaster tablet.
A portion of this combined metal was broken off and subjected to various chemical tests, which utilized HNO3 + H2O to dissolve some of these fused metals and precipitate salts using the reagents sodium chloride, potassium dichromate and potassium Iodide.

This photomicrograph illustrates that these metals do not like each other well enough to form a bead of obvious metal.

Sme of this metal bead was digested in 1 drop of nitric acid and drops of water, which after several minutes a single crystal of NaCl was placed in the solution. Although there was a Chloride precipitate, no obvious PbCl formed. Also added a KI crystal in another part of this solution, which produced a red-brown precipitant that is in part PbI, but the red-brown is an unknown and might be an Iodide salt of Bi..This reddish-brown color may also be due too much HNO3 and not enough dilution causing the KI to partially reduce to Iodine. More tests are needed. Examine #4 for better details.

Because the nitric acid digestion was essentially not a good showing, the same metal was thoroughly rinsed in water and rinsed again in concentrated HCl then placed on another glass slide to which was added 3 drops HCl & 1 drop HNO3 to create Aqua-Regia. Then it was heated to boiling till dry. Then this dry area was exposed to 2 more drops of concentrated HCl and boiled dry again and this same procedure was repeated 2 more times to eliminate any nitrates and create only chlorides.

10x – After the 4th time of driving away any nitrates a single drop of concentrated HCl was placed on slide in the dry area and a couple small KI crystals were added to the HCl solution. Immediately there was a dense black precipitant as this image depicts.

The next image illustrates what happens after 20 minutes:

10x – The KI precipitated the black as the above image demonstrates, but after 20 minutes different black crystal forms began to appear, as well as the slightly yellow band in-between the two black areas.
The yellowish glob to the right is the remnant of a KI crystal.
Perhaps, if the original metal bead was boiled a couple times in A-R instead of just once the concentration would be more, thus possibly the KI would have produced a more coagulated black precipitant. Then again, because there is Pb, Sb, S, Bi & Te present many factors are at play, which can also cause interferences in what drops out of solution as a precipitant.
Nevertheless, in this particular circumstance I strongly suspect that the blackarea and individual black crystals are primarily Te and not reduced Iodine, because of the care taken to remove nitrates.

To another portion of this solution was added a single crystal of potassium dichromate, which produced no precipitant.

Placed a toothpick in the original A-R before reagent chemicals were introduced, but there was no metal reduction on the toothpick. The only important aspect noticed during the toothpick fusion was an unpleasant strange odor that I cannot quite place where I have smelt it previously.

Of interest is that the fusion (combining these metals) on plaster tablet produced the typical accumulation of bladed crystals in the areas that were shelted from the torch flame. Plus, much too my pleasure there are also the stacked cubic (Bi?) structures. But, oddly the remaining SbS fusions did not have the typical bladed or cubic stacked crystals as shown in next image.

70x – This is an image of what I call bladed black crystals that have a decidedly a blue tint.
These types of blackish-blue bladed crystals are often a common occurrence when fusing or strongly heating SbS (Stibnite) and are so small that a microscope is required to see them. Although I have occasionally and inadvertently made very large crystals they are seldom large enough to distinguish with the naked eye.

This portion of data is only added to represent the occassional frustrations that are part of these types of chemical tests.

Note: many other reagents can and should be utilized to confirm or deny the presence of any metal. However, for the present set of images and supplementary text only the simple straight forward reagents (KI, K2Cr2O7, NaCl) are utilized.

4… Pb + SbS + Bi +Te + Ag

This test with a small high purity silver prill was also alloyed with 2 additional grams of Pb, which were all re-melted together in a boneash cupel and then cupelled.
The addition of 99.95% Lead was to allow better cupel absorption.
Based upon the troubling results I probably should have used 10 grams of Lead metal to cupel with. But, in spite of troubles these tests help me better understand how to possibly deal future mineral/metal complexities.

The cupellation took far longer than normal suggesting that the impurities were causing cupellation problems.

The following image shows the end result of the Pb+SbS+Bi+Te+Ag in cupel

20x – The end result of what would normally be considered a botched cupellation.. Obviously this is a mess with all the semi-metallic looking blacks and orange grunge which partially hiding the metal bead at about the 2 o’clock position.
The grunge is an clear signature of serious contamination that would not absorb into the boneash.

40x – A closer view of the black semi-metallics, which may be a form of Te, as well an accumulation of metal spheres near center of image.
Not able to focus on the entirety due to various heights of grunge and metallics.

40x – A much better view of the obviously contaminated silver that is blackish grayl. In fact this would normally be considered a disaster and not worth pursuing. However, I don’t throw away these undesirable assays, because all mistakes or errors are lessons to be learned. So, I do what others won’t – I keep digging trying to get a better idea about the why’s and what went wrong.
Good or desired results are hard enough to comprehend, but to try to explain and photograph just isn’t normally seen or discussed. It’s almost like saying mistakes are never encountered, which of course is utter nonsense.

The black looking metal was removed and surface etched in nitric acid and water as good as possible. Then this blackish bead placed on another piece of bonash and cupelled.

40x – Even this 2nd cupellation ended in another mess. Obviously the silver is so contaminated with Te and possibly other original metals that grunge is piled all over the silver bead that can be seen with this magnification, but not with the eye.

50x – Retrieved the silver prill from the cupel and tried to slowly use diluted HNO3 acid to strip away as much of the grunge as possible.

50x – The contaminated silver prill is almost free of the adhering grunge.
Presumably , based upon other tests the blacks are forms of Tellurium. These blacks stayed in the silver all the way to complete digestion.
The blacks also slowly dissolved.

50x – The blacks are laying on slide, but eventually dissolved.
There is the pinkish hue on this silver suggesting that Bismuth has contaminated the silver, which is a common nuisance.
The yellow-orange pieces are the grunge that was tenaciously clinging to the contaminated silver prill.

50x – After the prill was digested the nitric acid/water solution was becoming super saturated causing this crystal formation to precipitate along the perimeter of solution. This is obviously not a pure silver solution precipitant.
These images are placed here to possibly help other detect similarities when silver prills are digested under the microscope.
Normally, assayers would not consider taking this much time (hours) trying to understand what is happening.
If such an obviously contaminated prill was found in a cupel the assayer would simply throw it away. Like I said – there are clues and I want to learn about. Furthermore, this kind of data is not mined in books.

50x – As the solution continues drying this perimeter of saturated nitric acid the structure of the saturated nitrates change.

50x – The solution becoming more dry naturally.
Saturated solution crystal formations like this are good clues as to what to watch for. Note: It is at least my nature to being in a rush to see what crystals will form by adding heat, which is ok, but, there is the price of usually not being able to see what will form naturally.

50x – The solution became dry, so one drop of water was added to solution area and a single K2Cr2O7 crystal was placed in the now diluted solution residing upon glass slide. Although red colored blades are growing on this crystal of potassium dichromate they are not classic pure silver.
The tiny yellowish crystals towards the 3 to 6 o’clock position are most likely Pb chromates forming.

50x – This image attempts to show how Pb chromates are flowing away from the potassium dichromate crystal.
The red precipitated crystals are from the potassium dichromate crystal and are likely contaminated silver chromates.

50x – As the diluted solution nears dry these red crystals have formed and are not indicative of silver chromate, although silver is likely present.
There are orange crystal growths at 6-7 o’clock positions intermingled with the much smaller yellowish Pb chromates.

50x – Placed a toothpick tip in the solution prior to any additions of reagents that would cause precipitants, so that only what is in the solution might be reduced to metal when the metal laden acid impregnated the wood fibers when the oxidizing or reducing parts of a cigarette lighter flame ignited the toothpick tip.
The tooth pick tip was barely ignited twice to obtain this mass of tiny beads that are barely visible. I could have used higher power, but because the microscope can only focus on one plane, higher magnification is just too difficult to obtain an over-all view.

5… Pb + SbS + Te

10x – The Lead, Antimony sulphide (stibnite) and Tellurium fused into a single mass on plaster tablet. This metal blob does not resemble shinny metal, but was somewhat shinny when in a molten state.

20x – The above pictured metal was placed the solution of 1 drop nitric acid and 2 drops water, with a little heat to promote the digestive action.
The solution became too dry so was going to add another drop of HNO3 and 2 drops of water, but when 1 drop HNO3 was added 1st an immediate white precipitant formed. This white precipitant is likely Sb, because antimony does not like to stay in suspension in concentrated nitric acid.
Next, 2 drops of water was added and the white precipitant was not altered, further indicating Sb.
The precipitant is actually whiter than shown here because lighting is reflected causing a yellow cast.

10x – Another sample of Pb+SbS+Te conducted at a later date, basically showing same result as the above image, but the colors are more accurate here due different microscope and lighting. Again, the probability is that the white mass is Sb.

Ran a toothpick check and metal balls formed, but were too small to get a decent image of.

50x – This image shows the gel-like white (Sb?) crystals, as well as transparent crystals which appears to be Lead Nitrate.

50x – To confirm the presence of the metals in solution a couple small K2Cr2O7 crystals were placed in the solution. It did not take long for an grange and yellow precipitant to form. The yellow crystals not easily seen here are likely Pb, however the yellow crystals became totally captured by the orange precipitant.
The K2Cr2O7 does not seem to react with the white gel-like crystals, suggesting that potassium dichromate is not conducive to identifying Antimony.

50x – The potassium dichromate has become partially decrepitated.
The next image zooms in on the individual orange crystals not easily viewed with this magnification.

70x – The magnified previous image.
The solution is almost dry and these orange crystals are the only precipitant caused by the potassium dichromate.
The white (Sb?) crystals are unaffected by the potassium dichromate.

50x – A single sodium chloride (NaCl or table salt without any Iodine) placed in a different position but unaffected area within same solution as shown in preceding image. This salt crystal immediately began forming the traditional PbCl crystal growth. But, these crystals do not show any inclination to form the normal Pb feathers which suggests interfering contamination, which may be due to the Te and/or Sb.

50x – Added a single crystal of KI (potassium Iodide) to same solution as mentioned above, but in a isolated area unaffected by the other additions. Prior to adding the KI two drops of water was added to significantly dilute this portion of solution.

The image has captured a yellow band of precipitants at left of center and is typical of Lead Iodide.
The orange and reddish brown areas are question marks, because KI does not like a nitric acid environment and therefore the dark reddish brown at top of image may be a KI and tiny amount of HNO3 reaction. However the different orange colors may be indicating Sb and/or Te? In order to get a better idea, will have to conduct tests where the original metal bead is subjected to concentrated HCl and perhaps converted aqua-regia, then use same chemicals to get validations.

10x – The exact same test as immediately above (1 drop HNO3 + 2 drops of distilled H2O), but ran at a different date and further diluted by 3 additional drops of water for a total of 7 drops of water, which immediately produced when adding 2 small KI crystals the classic yellow Lead Iodide precipitation. This demonstrates that good results can be achieved with KI in nitric solutions, but for me a lot of trial and error is required.

The next image is of the same area as shown here, but magnified to better illustrate the white to gray precipitate laying close by and all over the bottom of solution.

40x – This image shows a bunch of whitish-gray precipitated crystals close to the Lead Iodide crystals that resemble gelatinous silica, but is not silica.
The best way to identify this white-gray stuff is let all the solution dry and carefully scrape off this white stuff and run tests on it, which I am not going to do, because it is too tedious and time consuming.

50x – The original PbSbSTe metal blob used in the above prior test solutions was now rinsed in distilled water then rinsed in concentrated HCl to strip away any nitric acid. Then this metal bead was placed on another clean slide and submerged in concentrated HCl and heated. The heat generated with this HCl eventually caused these crystals to form on the perimeter of solution as a result of drying and super-saturation.

Although I did not smell the odor of sulfur in the nitric acid digestion I sure was aware of the sulfurous odor with concentrated HCl when heated, which liberated to liberate these copious vapors.

Although I avoid breathing fumes from fusions or these microchems it is often unavoidable and I find significant data with these odors, which are quite varied and not likely to be noticed any other way.

50x – more of the super saturated crystals in same concentrated HCl solution.

50x – When a KI crystal was first added to the HCl solution no precipitant formed except for a pretty yellow color of solution surrounding the KI crystal. Then the KI began causing some precipitation and solution colors especially along solution perimeter where the clear saturated crystals had formed in the previous image. .
Not able to focus upon all the crystals accurately because some crystals are taller than others, so settled for a balance to minimize the length of time it takes to capture all the aspects to this procedure and not miss something that can happen spontaneously.

50x—In same HCl solution these radiating white to clear crystals formed next to the metal bead as a result of the KI, which I suspect is a form or Pb. Plus, there are also red precipitants forming at right of the white crystals that the KI apparently is causing. Don’t know what these tiny red crystals are.

By accumulating a battery of images using various acidic mediums and a variety of chemical precipitants considerable clarification can be accomplished as to what a mineral is or not.

Ran a toothpick test on the HCl solution, but it failed to reveal any metal.

40x – This image is of a A-R solution that was converted to a chloride state with 4 evaporations using concentrated HCl, to which 3 small KI crystals were added, which produced this group of blacks.

The reason that 3 KI crystals were added instead of 1 is a result that when I used a wetted tip of toothpick to grab hold of the KI instead of what my eye saw there were actually 3 tiny KI particles.

10x – This is the same image as above, but at a reduced magnification.

By the time I was able to capture this image the KI crystals of the above image had dissolved.

It appears that this black formation made-up of zillions of tiny crystals is one of the forms of TeI and not a KI reaction with residual HNO3,

6… Ag + Te

35x – The Ag+Te fused together on plaster tablet.
This metal bead was removed from the plaster tablet before I thought about capturing that portion of all images. Unfortunately, my primary motive was so focused I simply over-looked that detail, which shows that a preplanned sequential methodology has considerable merit.

The area at about 6 o’clock on this metal bead has a slightly raised pearly looking surface and the rest of prill is essentially blackish-gray with a metallic appearance..
The reddish orange areas are only light reflections.

20x – The AgTe in solution in the act of being digested in 1 drop HNO3 & 3 drops H2O.
The reddish-orange coloration is due to extraneous light reflections.

50x – The AgTe prill digesting in 1 HNO3 and 3 H2O, creating piles of shinny metallic looking black crystals accumulating on the glass slide.
The out of focus Ag+Te bead is to the upper left corner..

50x – Some AgTe crystals due to super-saturation are forming along perimeter of solution.

50x – The AgTe in a saturated solution produced these forms of crystals, which is clearly not Silver, but may be a combination of both elements.

70x – More of the super-saturated Ag+Te crystals within the boundaries of the larger white crystals

I do not know what these crystals are, but are apparently some kind of nitrate combination.

50x – To the same HNO3 + Ag+Te solution was added 2 crystals of NaCl, which instantly formed the typical silver chloride precipitant that keeps expanding till all the NaCl is consumed or the amount of silver nitrate in solution becomes AgCl.

If this AgCl is left to sit for several minutes to a few hours the bluish rose-purple color will form, eventually becoming black because AgCl is light sensitive as seen in the next image.

50x – As the preceding solution continues drying and the light within the room shines on the AgCl precipitant it is slowly turning lavender along the edges.

50x – The Ag+Te nitric acid solution with a single introduced crystal of potassium dichromate is forming what appears to be a typical silver chromate precipitant growth of red crystals. However, although one would say that silver is present these red crystals are a little different than what a pure silver solution would produce. So, apparently the Te is influencing these red crystal growths.

70x – A magnified view of a portion of the red (Ag+Te) crystals in the above image.
As the solution dries the red silver chromate crystals continue growing.
Reflected light is causing some of the red crystals at left to appear white.

50x – A toothpick tip is dipped into the Ag+Te + HNO3 + H2O solution This wood tip is exposed to the tip (oxidizing or highest heat source) of cigarette lighter flame, which produces (reduces) a series of wire looking metal strands and a few larger metal beads.

It took 2 relatively short exposures to the flame for this metal format to show good enough to be photographed. Often, metal formed in this manner can be further consolidated into a large metal bead with more exposures to hot flames.

7… Te + S

10x – Te + Sulphur fused on plaster tablet.
Obviously this black mass does not resemble Te as a metal.
This rather grotesque form of elemental sulphur which I covered a few small pieces of Te then used the Mapp gas torch flame to fuse indicates that if anything remotely similar to this was found in a rock it would not be recognized.

The hope was to obtain tellurium that chemically combined with the sulphur to form a sulfide or something close which I could eventually identify with acids and chemicals.

20x – From the above plaster a piece of the semi-brittle Te+S fragment on a slide with 1 drop nitric acid and 2 drops water and heated.
When the solution was drying a super-saturated white precipitate formed, which is the same as happened in the Te only test. Therefore, if Te does not have a lot of interfering contaminates this white curdy looking precipitant will form.

When dry and 2 drops of water was added the white precipitant does not dissolve, but when HNO3 is added the white mass it readily goes back into solution.

The addition of a Potassium dichromate crystal only produces a red solution and no precipitant.

20x – Forcing the solution containing the potassium dichromate crystal to dry continues to produce a deep red coloration, which is almost black, but nearby the previous white is turning a pretty light sea green.
At the right of image some of the red can be seen infiltrating the white area.

The greenish color may only be a liberated chromium salt.

20x – After rinsing in water, followed with a concentrated HCl rinse to expel any trace of nitric acid the same Te+S fragment is placed on another glass slide.
3 drops of concentrated HCl acid is placed on the fragment and heated.
After 2/3rds of the HCl had evaporated a crystal of KI was inserted into the solution, which produced no immediate precipitation.
Eventually, after several minutes these outer periphery dark bands formed, suggesting that KI is reducing some form of Te.

These types of bands should not be construed as positive proof of anything, but might be a clue for future tests.
Higher magnification does not provide any help in determining what these crystallized bands are because there is no specific structure.
When the solution is almost dry the higher magnification does reveal a reddish color verses brown or black. Unfortunately I could not capture this exact color image.
The conclusion of this set of microchems provides evidence that Pb can be found in the nitric acid, but with great difficulty in the converted Aqua-Regia (A-R) solutions.
The A-R indicates the presence of Tellurium (Te).
Neither the nitric nor A-R solutions provide evidence for Bi.
Sb is best found as a whitish super-concentrate when the nitric solution is more acidic than diluted with water.
Ag was identified rather easily in nitric acid, but Pb can cause serious interference and was not positively found except in the one instance.

Even though a couple of these tests proved that adding acid or water to concentrated solutions can and will either digest or precipitate one or more of the elements, no attempt was made to determine nor carefully manipulate pH levels.

I prefer to always start microchems using concentrated acids and as few precipitating reagent chemicals as possible. In other words I try to keep it simple, if possible.

Finally, although finality is a long way off, it's crystal clear that other reagents are necessary to prove when and if Te is present when numerous other potentially interfering elements are known or likely to be present in any of the solutions.