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 have fallen in love with the Ural's old storyteller P. Bazhov". Selected stories have been a part of school core curriculum since the Soviet Union, and are still used for education purposes nowadays. The Ministry of Education and Science of Russia included the tales in their 2013 list of "100 Recommended Books" for schoolchildren. Their effective pedagogical influence have been noted. "The Malachite Box" became a classic of Soviet children's literature, yet the stories continued to be popular among adults as well. Mark Lipovetsky believed the situation in the author's life added to the depth of the tales and made