Sugilite | |
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Sugilite from Wessels Mine in Northern Cape Province , South Africa | |
General | |
Category | Cyclosilicate |
Formula (repeating unit) | K Na 2(Fe ,Mn ,Al )2Li 3Si 12O 30 |
Strunz classification | 09.CM.05 |
Dana classification | 63.02.01a.09 |
Crystal symmetry | Hexagonal |
Identification | |
Formula mass | 1,041.66 |
Color | Light brownish-yellow, purple, violet, reddish violet, pale pink, colourless |
Crystal habit | Granular |
Mohs scale hardness | 6–6½ |
Luster | Vitreous |
Streak | White |
Diaphaneity | Transparent to translucent |
Specific gravity | 2.74 |
References | [1] [2] |
Sugilite (also known as lavulite ) is a relatively rare pink to purple cyclosilicate mineral with the complex chemical formula K Na 2(Fe ,Mn ,Al )2Li 3Si 12O 30. Sugilite crystallizes in the hexagonal system with prismatic crystals. The crystals are rarely found and the form is usually massive. It has a Mohs hardness of 5.5 to 6.5 and a specific gravity of 2.75 to 2.80. It is mostly translucent.
Sugilite was first described in 1944 by the Japanese petrologist Ken-ichi Sugi (1901–1948) for an occurrence on Iwagi Islet, Japan , where it is found in an aegirine syenite intrusive stock. It is found in a similar environment atMont Saint-Hilaire , Quebec , Canada . In the Wessels mine in Northern Cape Province of South Africa , sugilite is mined from a strata-bound manganese deposit. It is also reported from Liguria and Tuscany , Italy ; New South Wales , Australia and Madhya Pradesh , India .
Note: The mineral is commonly pronounced with a soft "g", as in "ginger". However, as with most minerals, its pronunciation is intended to be the same as the person it is named after; in this case, the Japanese name Sugi has a hard "g", as in "geese": / ˈ s uː ɡ ɨ l aɪ t / soo -gi-lyt .
A rich thumber of pretty purple sugilite on a matrix of bladed barite crystals, Wessels Mine inNorthern Cape Province , South Africa , size: 2.4 x 2.1 x 1.2 cm.
Sugilite tile
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