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
Italian submarine Malachite she again patrolled of Ras Aamer. From 11 to 23 February, 1942 she was deployed to an area off the coast of Cyrenaica. From 8 to 21 April, 1942 again she was again deployed off the coast of Cyrenaica. From 1 June to 9 June, 1942 and then again from June 15 to 18, 1942 "Malachite" was posted northwest of Algiers. She was then relocated to patrol off Cape Blanc from 22 to 24 June. On July 16 1942 "Malachite" was sent to patrol along the Tunisian coast, however had to return to the base the next day due to