30x – A Selenium metal sphere that has the characteristic dimple..

30x – Fragments of a Selenium metal sphere.
This metal is very brittle and glassy. Although it looks black, similar to obsidian glass there are hints of red in thin slivers.

40x – A Selenium sphere fragment that was used to generate the next 5 images.

25x – The preceding image of the selenium fragment that is now in 1 drop of water and 1 drop of HNO3 on glass slide that was gently heated and is very slowly dissolving.
Although this 1 part water & 1 part nitric acid dissolves selenium, HNO3 without water works best. The next image is generated with only nitric acid without any water.

25x – The solution has come to dry with continued application of heat applied to underside of glass slide.
A unique twining of the drying crystal formations.
In subsequent micro-chems using only HNO3 to dissolve the selenium there were sometimes 3 or four crystalline formations that developed with the same radiating fibrous appearance.

40x – At the base of the partially dissolved selenium fragment is a white curd which is also rather unique and may be a clue when trying to detect selenium in a nitric acid solution.
When another drop of concentrated or diluted nitric acid is placed on the dried super-saturated crystal formation all crystalline structures go back into solution.

20x – A single crystal of K2Cr2O7 was inserted into this concentrated nitric acid solution that has dissolved a small fragment of selenium metal.
There was no immediate or long-term precipitant.

20x – The K2Cr2O7 crystal has completely dissolved in the solution of Selenium and HNO3.
Because there was no precipitant after waiting an hour gentle heat was applied to the glass slide creating this appearance of the dissolved potassium dichromate crystal.

When more heat was applied to drive the solution to dry there was a reaction and no precipitant would form, nor would the solution come to dry without irritating fumes.

10x – In another solution where 1 drop of HNO3 partially dissolved a selenium fragment 3 additional drops of water was added to dilute the nitric acid. Then, a single crystal of KI (potassium Iodide) was inserted into the solution causing the instant formation as seen in this image.

Because KI has a strong tendency to reduce in a HNO3 solution I suspected that this rusty area was due to a reaction between the KI and HNO3. However, after an hour no Iodine was reduced. So heat was gently applied to the underside of the glass slide to slowly drive off water as vapor to see if Iodine would reduce as normally occurs. However, no Iodine was reduced as seen in next image.

10x – The preceding image solution containing HNO3 + H2O and dissolved Selenium as seen here is almost dry and surprisingly no reduced Iodine formed. Therefore, it appears that Selenium reacted with the potassium Iodide to form this rusty colored solution and crystal formations shown in next 2 images.

40x – A magnified view of the preceding image better illustrating the crystalline structure(s) that may be a direct reaction of KI and dissolved Selenium.

40x – Another magnified view of the crystal structure(s) in the preceding image.

Because I am skeptical of this test I ran another to help determine if the KI was reacting with HNO3 or actually causing this rather odd precipitation, which is further illustrated in the next 3 images.

10x – A fragment of Selenium was dissolved in 1 drop of HNO3.
The HNO3 solution was diluted with 1 drop of water.
Then a single crystal of KI was inserted into this nitric, water and dissolved selenium, which created this instant reddish brown reaction.
This appears to be a reaction of Iodine and HNO3, but waiting did not produce the typical expected reaction, which continues to raise questions.

10x – After 15 minutes the preceding image became what is shown in this photomicrograph.
At this magnification there appears to be the typical black reduced crystals of Iodine, but higher magnification does not substantiate this conclusion.

10x – After another 30 minutes the preceding picture became this image.
I am still unsure if this is an actual Selenium precipitation or simply an unusual reaction between Iodine and HNO3?

Obviously this microchem demands further testing to confirm or deny whether or not KI is a suitable reagent to use in determining the presence of Selenium in a nitric acid solutions.

Placed a Selenium fragment in concentrated HCl and because there was no reaction a cigareete lighter flame was placed under the glass slide to speed-up a reaction, which did not occur. More and more heat was applied with only a hint  that heated HCl has a dissolving effect on the Selenium metal.
No definable super-saturated deposit occurred on the glass slide. So, because the selenium metal fragment indicated some reaction to the hydrochloric acid a crystal of K2Cr2O7 was inserted into the solution. This potassium dichromate failed to produce any results that could be helpful in determining the presence of dissolved Selenium.

The next two images are the result of adding KI to a concentrated HCl solution that dissolved some Selenium

10x – A KI crystal (center of dry solution) was inserted into the HCl solution that has attacked to a slight degree the Selenium Metal fragment.
No color or precipitant formed as a result of  the KI insertion.
Based upon previous microchems KI does not produce any convincing evidence of dissolved Selenium in a HCl solution.

40x – A magnified portion of the dried solution of the preceding KI solution.
There are some rather unique crystal formations, but I would not consider using these types of crystal formations as reliable indicators of Selenium in HCl.

Based upon only the 2 reagents used here the best identifier of Selenium is the dried HNO3 solution without any added chemicals.

When time and circumstances allow this and the others will be expanded upon to provide verifiable and convincing evidence of the best chemicals to use in determining what metals are present in either a HNO3 or HCl solution. I doubt that I will ever get around to presenting images of HF and H2SO4 solutions.

10x – This toothpick tip was dipped in the HNO3 (no water) solution that had dissolved some Selenium metal.
The dried toothpick tip was ignited and no evidence of any metal formed. There was a slight amount of an unpleasant odd odor, but did not resemble the rotten horseradish smell that Selenium is famous for.

40x – A magnified view of the preceding image of toothpick tip that was reignited and now shows evidence of a metallic brownish black residue.

40x – The toothpick tip was ignited again and there is more evidence of a metallic tip. I cannot state if this metallic looking toothpick tip is metal or an oxide of Selenium, but this image clearly illustrates that Selenium was reduced to some degree