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 kingfisher A molecular phylogenetic study published in 2007 confirmed that the most closely related species is the Malagasy kingfisher, ("Corythornis vintsioides"). The Malagasy kingfisher has a black bill and greenish crest, and is not quite as dependent on water as the African species. It is otherwise similar in plumage and behaviour to the more widespread malachite kingfisher. The São Tomé kingfisher and the Príncipe kingfisher were sometimes considered as distinct species but a study published in 2008 showed that they are both subspecies of the malachite kingfisher. There are five subspecies: This is a small kingfisher, around in length. In Southern