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 some information about the life, industry and culture of the Urals and which the author tried to include into every edition of the collection. Later versions contained more than 40 stories. Not all stories are equally popular nowadays. The most popular tales were written between 1936 and 1939: "The Mistress of the Copper Mountain" and its continuation "The Malachite Casket", "The Stone Flower" and its continuation "The Master Craftsman", "Silver Hoof", "Cat's Ears", "Sinyushka's Well", "The Manager's Boot-Soles". Among the later stories, "A Fragile Twig" (1940), "The Fire-Fairy" (1940), "Tayutka's Mirror" (1941), "Ivanko Krylatko" (1943), "That Spark of Life" (1943)