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 sunbird sunbird species can take nectar by hovering like a hummingbird, but usually perch to feed most of the time. As a fairly large sunbird, the malachite sunbird is no exception. They have long thin down-curved bills and brush-tipped tubular tongues, both adaptations to nectar feeding. Some plant species from which malachite sunbirds feed include many "Aloe" species, such as "Aloe broomii", "Aloe ferox" and "Aloe arborescens", and "Protea" species, such as "Protea roupelliae" as well as various other bird-pollinated plants such as "Leonotis" and "Strelitzia". It has been suggested that their behaviour of guarding flowering plants may have led to