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
Malachite Room of the Winter Palace Malachite Room of the Winter Palace The Malachite Room of the Winter Palace, St Petersburg, was designed in the late 1830s by the architect Alexander Briullov for use a formal reception room for the Empress Alexandra Fyodorovna, wife of Nicholas I. It replaced the Jasper Room, which was destroyed in the fire of 1837. The room obtains its name from the use of malachite for its columns and fireplace. This large salon contains a large malachite urn as well as furniture from the workshops of Peter Gambs (1802-1871), son of the famous furniture maker Heinrich Gambs, which were rescued from