50x – 99.9% pure Bi crystals. Some of the Bi fragments are sort of white, but most have a dark oxide film making it difficult to get a decent representative image.

Striations and laminar deposition seems to be what happens when an induction furnace is used to melt this metal.

One drop of HNO3 was placed on the Bismuth and there was an instant attack, which quickly digested these metal fragments creating a definite yellow solution color.

When digestion of the metal was complete added 1 drop of water to dilute the solution which formed no precipitant.

50x – a single crystal of Bismuth in 2 drops HNO3 and 1 drop H2O, which produces a very vigorous digestive action.
Notice the pinkish coloration on the metal fragment as it dissolves.

30x – As the Bismuth dissolves a single drop of water added to the pregnant HNO3/water solution instantly produced this white, semi-transparent crystal formation.

40x – This toothpick tip was dipped into the 2 drops nitric and 1 drop water solution which was heated and after a few minutes being reasonably sure that enough of the Bismuth had dissolved to adequately impregnate the fibers of toothpick.
When the toothpick tip was ignited with the flame of a cigarette lighter and quickly placed under the microscope dozens of tiny molten beads of metal could be seen. When the burning ceased several of the beads solidified as seen here. However, many of the molten beads became a yellow-orange grunge indicating that some bismuth nitrate and although the wood becoming carbon reduced the bismuth some nevertheless oxidized.

The following images are of another microchem being applied similarly to the preceding. However, instead of 1 drop of water and 2 drops nitric acid, this time it was 2 drops of water and 1 drop of nitric acid to initiate the dissolving action.

The next image shows what happens as heat is applied to the solution which slowly vaporizes causing super-saturation of the bismuth nitrate.

50x – as the nitric and water solution became super saturated bluish-white tiny crystal formations began to appear at the perimeter of solution on the glass slide.

70x – This is a magnified view of the prior image, providing a better perspective as to what these saturated Bi crystals look like.

25x – By adding 1 drop of water to solution this instant precipitation formed.
By adding 1 drop of HNO3 the white precipitation re-dissolves.The question becomes will this precipitation occur if other metals are also in solution?

To this same solution a single crystal of NaCl was added and at opposite portion of solution a single crystal of potassium dichromate (K2Cr2O7) was added. Neither reagent produced a precipitation, although potassium dichromate made an orange color.

Concentrated HCl has no effect on Bismuth metal.

Dissolved more Bismuth metal fragments with A-R, which slowly attacks the metals.

50x – When the Aqua-Regia (A-R) solution semi-dried these types of crystalline and massive white structures covered the whole area of slide.

50x – Converted the A-R to a chloride state and this crystal formation occurred when solution was dry. Heat was used to speed-up the process otherwise this solution would take hours to dry on its own. Keep in mind that forcing a solution to dry can distort crystal formation.

50x – to the prior dried state of converted A-R solution a drop of HCl was added to bring the dried crystals back into solution then a single crystal of KI was placed in this solution.. There was no immediate precipitation, but as the solution was coming to near dry this red area formed.
This particular part of the micro-chem will have to be re-ran because I suspect some nitrate interference is causing the Iodine to reduce, which is always dark red then black, resembling this scenario. If this is a nitrate problem it typifies why it is extremely important to be sure that no area of the glass where the solution was that had any nitric acid that had been converted to a chloride state or face re-doing the time consuming procedure, which is likely what happened here. The rule for me is – when in doubt do it over till reasonably sure that errors were not inadvertently introduced.

50x – A toothpick tip was dipped in the nitric acid solution that dissolved the Bismuth and then ignited. As the toothpick burned small metals beads formed but quickly oxidized to this yellow grunge on the circumference of toothpick and an orange grunge in center of toothpick.
A compromise on focus was necessary to obtain an overall image.

It seems as though how strong the nitric acid is or how much metal is actually in solution and/or what part of the flame (oxidizing or reducing) burns the wetted wood determines how much metal is captured or seen.

It appears that the best assessment for dissolving pure Bismuth is in nitric acid and adding a couple drops of water, which forms a specific precipitate coupled with the toothpick assay.

Seldom does any element occur in such visible abundance that its physical properties can be ascertained visibly. Therefore, in many instances a metal like Bismuth will be quite intimate with one or dozens of other elements, each possibly as desirable as Bismuth. Consequently, by doing a little prospecting with solutions Bismuth might be able to be found when other common tests miss it.

Bi + Pb

25x – A small amount of 99.9+% pure Lead and Bismuth were fused into a single bead. Because this bead is large higher magnification causes too much distortion and won’t allow enough detail. So, this magnification is a compromise of detail, color and over-all texture of the merged metals.
As you can tell I don’t have the best lighting facilities. Sometimes I can employ multiple light sources to obtain a great image, but usually too much light causes too many reflections that distort the image.

50x – The Lead and Bismuth bead was submerged in 1 drop of nitric acid and 2 drops of water, which is digesting the PbBi bead. As the solution begins to dry super-saturation crystals begin forming at perimeter of solution. This image captures a few of these crystalline formations.

50x – the surface of the PbBi bead has basically turned blackish within the nitric acid solution.
Adding water does not precipitate anything. In fact the saturated crystals that formed previously re-dissolve within the water.

50x – Placed a single crystal of NaCl which immediately began to form a white precipitate which grows forming these needles. There are no Feathers normally associated with PbCl.

A single crystal of potassium dichromate placed in this solution failed to produce any precipitant, which is a bit odd, because it usually provides additional proof if Pb is present.
I am left speculating if the solution is too weak, too strong or perhaps these two metals so closely linked on the periodic chart cause interferences, which won’t produce typical precipitations of either metal alone? Obviously more microchems are required to find the answer.

50x -- Out of curiosity a single crystal of KI was placed in an isolated area of the solution and there was an instant reaction where the Iodine partially reduced, but did not quite complete reduction leaving a brown mass.
If not familiar with what KI within various strengths of HNO3 produce a novice would think this brown mass was a precipitation relating to Bismuth and/or Lead.
By experimenting one learns what to sometimes expect, but surprises are occasional so it is wise to not take for granted anything till proved.

50x – To another solution that was conducted exactly like the previous it was further diluted with two more drops of water and then was added another crystal of KI.
Although the Iodine tried to reduce (red color) there was also the yellow Lead Iodide crystals confirming the presence of Pb.
Clearly, more dilution is warranted if KI is to prove the presence of Pb.

50x – A toothpick was dipped in the original nitric acid solution prior to any introductions of reagents. There were lots of small beads of metal, but they for the most part oxidized into orange and white non-metal balls. There are a couple metal beads visible, but it appears that bismuth combined with lead does not like to stay in metal form.

Although this microchem did not confirm the presence of bismuth it has shown what to be wary of.

More testing is required, and when time permits more data will be added.

Bi + Ag

Image at far left is the below photomicrograph.

10x – This Bi+Ag combination created a skim coating on the metal bead that does not typify either Bi or Ag alone. The sublimate fades drastically in a few days.

25x -- The BI+Ag on glass slide in water only

40x -- A magnified view of the preceding image, which shows the surface grunge/slag (oxidized Bi maybe mixed with PbO).

25x – The Bi+Ag bead being dissolved in 1 drop HNO3 and 2 drops H2O.
There is a slight pinkish hue to the silvery metal, but this lighting enhances the pink too much.

25x – Super-saturation crystal forming as the Bi+Ag bead continues to digest in the remaining solution.

16x – Super-saturated Bi & Ag crystal growth practically consuming the whole solution area.
Removed the Bi+Ag bead and added 1 drop of water. An instant white appeared, but dissolved before I could capture a focused image.

10x – Added another drop of water and another instantly forming dense white precipitate, which also re-dissolved before I could capture it, but was able to capture this image.
There remained a few of white looking crystals in the upper left corner.

40x – Magnified view of the white crystals mentioned in previous image.
The point here is that adding water to a solution containing significant amounts of Bi will precipitate these white crystals.

35x – Bi + Ag in water showing some of the surface crystalline structure after it has been subjected to the nitric and water solution.
At this magnification, due to the curved surface it is impossible to focus and show detail of the whole bead, so a compromise must be made, which attempts to show a little detail over as wide an area as possible.

17x – the Bi+Ag bead being again digested in 1 drop HNO3 and 2 drops H2O on another slide.

12x – small amount of water added to the 25% nitric acid solution showing the instant Bi (white) precipitation around the bead.
There are very small crystals beginning to form on the perimeter of this bead as the next photo illustrates.

12x – these white crystals are growing out of the bead due to the addition of a single drop of water.
Only the bead is in focus.

12x – The microscope is now focused on the silvery-white crystals as they continue growing.
These white crystals are silver metal and have a dendritic or fern-like structure.
Apparently this phenomena is due to the metal Bismuth within the bead, which is reducing the silver that has been digested from the bead.

20x – Added a drop of nitric acid to the previous image's solution, which dissolved the silver growing crystals.
Then added another drop of water and there was an instant white massive precipitation of Bismuth nitrate or perhaps an hydroxide of Bi.
Then very slowly these dark (black) crystals began growing out of the bead.

30x – A closer view of the dark crystals growing out of or from the surface of the bead.

20x – Another overview and the Bismuth nitrates or perhaps Bismuth hydroxides are consolidating their shape or crystalline structure.

20x – After 15 minutes these silvery white crystals began growing above and below the dark crystals which also are very slowly growing.

20x – The silvery white crystals still growing within the acidic, but diluted solution.
No visible digestion of the bead has been taking place since the crystal growth began.

10x – an overview of the solution containing the bead and crystal growths.
After another hour the entire solution was covered with the silver white metal crystals, which dissolve with an addition of nitric acid. The dark crystals stopped their growth.

Possibly and most likely any base metal that is intimate with the silver and below silver on the electromotive table can initiate this anomalous crystal growth.

30x – Added this K2CrO7 crystals to the pregnant solution. It did nothing except turn from orange to this red.

10x – Because the potassium dichromate crystal would not grow any crystals I added another drop of water suspecting that the solution was too concentrated. All that happened is this white precipitation, which apparently is Bismuth.
Even with the addition of 2, then a couple more drops of water there was no significant change to this potassium dichromate red crystal.
Like all tests, they each deserve and demand intensive investigations, and this instance is certainly no exception.

30x – Added a single grain (crystal) of NaCl to see if Ag would precipitate.
There was an instant whitish precipitation, but it sure does not resemble silver chloride. Obviously, this precipitation is a strange combination of Bi & Ag.

40x – In another solution of Bi and Ag, but with a lot more water added during the initial digestion, a couple of NaCl crystals were introduced, which formed this immediate precipitation form.
Even though this precipitation resembles AgCl a lot more that the previous image, it is still heavily contaminated, and the only other element in this situation is Bismuth.

Starting with known’s is in my opinion paramount to getting a grasp on the potential crystal formations that occur when a powdered sample containing multiple minerals are digested in an acidic medium.

30x – To the same solution, but in a different area these 2 crystals of Ki were added. There was this instant precipitation.
The white appears to be AgI.
The blackish area I suspect is a Iodine reaction with the HNO3 in solution, but potassium Iodine, but the Iodine was not completely reduced as is normal in a too concentrated solution of nitric acid or nitrates.

40x – After an hour within the still liquid solution of the preceding KI precipitation now has this appearance.

40x – A toothpick was dipped into the original saturated solution and ignited, which produces zillions of tiny molten beads of metal, with a larger bead still near the front portion of glowing toothpick tip.
Most of the molten beads become a brown grunge, suggesting significant oxidation, which I presume to be Bismuth.
Likely the two metals are commingled with silver trying to reduce at same time, but the Bismuth, as it oxidizes won’t let the silver accumulate.