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 Fairy Tale" (), based on "The Mistress of the Copper Mountain". Based on "Marko's Hill", Klara Katsman created the operetta "Mark Beregovik" (), which premiered in Sverdlovsk in 1955. Lyubov Nikolskaya composed the children's opera "Silver Hoof" based on the story of the same name in 1959. Vladimir Goryachikh composed the ballet "The Living Stone" () based on "Sinyushka's Well", which premiered in Nizhny Tagil in 1965. The 1973 opera "The Fire Maid" (based on "The Fire-Fairy") for schools was composed by Robert Long, with story adapted and lyrics by Dorothy Gulliver The 2012 opera "The Malachite Casket", based on