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 of operations, she was attacked by an aircraft but the attack was beaten back with her anti-aircraft weapons. During the night January 27 1941 she patrolled in the Strait of Messina. From 9 to 18 February 1941 "Malachite" patrolled off Bardia. On February 14 she attempted an attack on an unidentified warship, but fails to launch torpedoes due to the high speed of the target. From 15 to 22 March 1941 she was deployed in the Kythira Strait. On the night of March 19, "Malachite" sighted a cruiser escorted by several destroyers. At 01:19 she launched two torpedoes but they