Colour

...can tell you a lot. The eye can be a wonderful spectrometer. This sample is, I think, a magnesium-containing inorganic material, and should be colourless. There is clearly something in there that shouldn't be, and the student doesn't know what it is. I'm not going to find out, but I'm interested to see if it changes colour once I have heated and evacuated it, hence this 'before' photo. If you are very lucky there will be an 'after' shot tomorrow.