Strange green and gold coloured chemical I have a reagent bottle with an unknown chemical that came with some other lab gear about 30 years ago, I stumbled on it again when clearing out some old stuff.

It is a standard brown glass Merck of about 250ml size.  It has no label and never had any indication of a label and I do not know if it is the original bottle.

The powder is a fine dark free flowing crystalline solid.  It is DARK green with a gold iridescent sheen when in bright light, something like a butterfly wing or some anti-forgery inks on banknotes.

Yet if I wet a very small portion it dissolves completely and creates a vivid dark blue solution that dries blue in a thin film.  If the crystals dry in a clump they form a smutty dark green gold pasty lump that is reminiscent of the original bulk colour.

I had to hand some potassium permanganate crystals and when I mixed a pinch of the two together and added a drop of water a gas evolved and the colour seemed to be somewhere between the permanganate and the mystery chemical blue when spread on paper.  Adding a few drops of acetic acid seemed to have no effect.

Can anyone think of an obvious candidate or some simple experiments that could be used to determine the material?
I worked for a time with squaraine dyes that were often greenish in the crystalline state, but ink-blue when in solution.



However, I would suggest that you take an analytical approach to identifying this compound.  Have you done any NMR, IR or even UV/Vis spectroscopy?  Elemental analysis?

These would be a much safer way to go about identifying the mystery compound.

Good luck, and I'd love to know what you discover!