Mineral Examples of such minerals are malachite (green) and azurite (blue). In contrast, allochromatic elements in minerals are present in trace amounts as impurities. An example of such a mineral would be the ruby and sapphire varieties of the mineral corundum. The colours of pseudochromatic minerals are the result of interference of light waves. Examples include labradorite and bornite. In addition to simple body colour, minerals can have various other distinctive optical properties, such as play of colours, asterism, chatoyancy, iridescence, tarnish, and pleochroism. Several of these properties involve variability in colour. Play of colour, such as in opal, results in
The Malachite Box and trauma, which Bazhov endured between January 1937 and 1938, and noted that "The Malachite Box" "is filled with unprecedented for Soviet (and especially children's) literature horror". At that time Bazhov was fired from Sverdlovsk Publishing House, where he had worked since 1931, and expelled from the Communist Party for "glorification of people's enemies" in his recent book. His past as a member of the Socialist Revolutionary Party and a seminary teacher was also questionable. He was once summoned for interrogation by NKVD, but luckily his investigator was arrested the day before the meeting. The author was reinstated in the