[ElementaryC]

When I recrysallized copper sulfate I bought at the hardware store, an unknown substance was found adhering to the copper sulfate crystals. It took the form of fluffy white tiny needle crystals.

Tests performed:
1. Insoluble in water
2. No change in appearance when heated to around 450°C in crucible on alcohol lamp
3. Turned a light grey when heated by the propane torch until the crucible glowed bright orange, but no change in the form - tiny needle crystals - did not melt.
4. Hardness: did not scratch or sand steel the way silicon dioxide would.
5. No apparent reaction with 30% Hydrochloric acid
6. No apparent reaction with 10% aqueous ammonia

This substance originated either in the copper sulfate from the hardware store, in in the tap water used in the recrystallization.

Does anyone know what this substance might be, or what further tests might be performed to determine its identity? I look forward to reading what folks have to say.

By the way, this is my first post ever here. I haven't figured out yet how to use the subscript for chemical formulas.

Thanks!

[billnotgatez]

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 I haven't figured out yet how to use the subscript for chemical formulas.
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There is a feature in the forum edit (Post reply) window that allows for subscripts.
Copper(II) sulfate pentahydrate (CuSO₄·5H₂O)

We have a Sandbox entry where you can practice
http://www.chemicalforums.com/index.php?topic=64128.0
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You might also want to read
http://www.chemicalforums.com/index.php?topic=59314.0