Spectrolite
Spectrolite is an uncommon variety of labradorite feldspar.
Colors
[edit]Spectrolite exhibits a richer range of colors than other labradorites as for instance in Canada or Madagascar (which show mostly tones of blue-grey-green) and high labradorescence.[1][2] Due to the unique colors mined in Finland, spectrolite has become a brand name for material mined only there. Sometimes spectrolite is incorrectly used to describe labradorite whenever a richer display of colors is present, regardless of locality: for example, labradorite with the spectrolite play of colors has sometimes described material from Madagascar.[1]
History
[edit]Finnish geologist Aarne Laitakari (1890–1975) described the peculiar stone and sought its origin for years when his son Pekka discovered a deposit at Ylämaa in south-eastern Finland, while building the Salpa Line fortifications there in 1940.
The quarrying of spectrolite began after the Second World War and became a significant local industry. In 1973, the first workshop in Ylämaa began cutting and polishing spectrolite for jewels. After that, a gem center was established in Ylämaa with training for gem-cutting accompanied by an annual Gem and Mineral Show initiated by Esko Hämäläinen, mayor of Ylämaa municipality.
References
[edit]Seppo Lahti I.1989 The origin of interference colours in spectrolite (iridescent labradorite).Geologi 41.
- ^ a b Michael O'Donoghue, Gems, Butterworth-Heinemann, 6th ed., 2006, pp. 238-267, ISBN 0-7506-5856-8
- ^ Walter Schumann, Gemstones of the World, Sterling, 3rd ed., 2007, pp. 52 - 53, 182 ISBN 1-4027-4016-6
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