Labradorite has the formulae (Na,Ca)AlSi3O8 and a relative hardness of 6. It is one of the plagioclase felspars, also known as soda-lime felspars. Others in the grouping are: albite, oligoclase, andesine, bytownite, and anorthite. Labradorite often has a beautiful display of colours. The name is derived from the locality of Labrador.
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