Reference work entry
Sunstone is also known as ‘sunlight stone’ and is an important gemstone of the plagioclase subgroup. It is commonly golden red or reddish brown and is usually translucent. Because sunstone contains metal flakes such as haematite and goethite, which are roughly uniformly arrayed, gold red rays reflect when the stone is rotated, resembling glittering gold sand; therefore, it is also called gold sand stone. It is mainly mined in India and the United States (Fig. 50).
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