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Formula: KNa2Fe3+2(Li3Si12)O30
Cyclosilicate (ring silicate), osumilite group,
lithium-bearing mineral
Crystal System: Hexagonal
Specific gravity: 2.73 to 2.79 measured, 2.80 calculated
Hardness: 5½ to 6½
Streak: White
Colour: Pale pink, light brownish yellow, purple, colourless in transmitted light. Pink to purple colour due to the
presence of Mn3+
Melting point: ~895oC
Common impurities: Ti,H2O
Environments
Plutonic igneous environments
Metamorphic environments
Sugilite occurs in stratabound metamorphosed manganese deposits and
in peralkaline igneous rocks
(Dana).
Localities
At Woods Mine, Darling county, New South Wales, Australia, sugilite is rare and occurs as small aggregates
associated with
serandite, namansilite,
braunite, albite and
manganese-rich
amphibole
(R&M 92.6.550-555).
At the Poudrette quarry, Mont Saint-Hilaire, La Vallée-du-Richelieu RCM, Montérégie, Quebec, Canada sugilite occurs
in marble xenoliths associated with
poudretteite, quartz,
polylithionite and pectolite
(Dana).
At the type locality, Iwagi Island, Inland Sea, Ehime Prefecture, Japan, sugilite occurs in
aegirine
syenite associated with albite,
allanite, aegirine,
andradite, apatite,
pectolite, titanite and
zircon
(R&M 92.6.550-555).
At the Bruce mine, Sishen, Kathu, Gamagara, John Taolo Gaetsewe, Northern Cape, South Africa, sugilite has been
found in a borehole core as blebs to about 1 mm associated with
albite, armbrusterite,
norrishite and serandite
(R&M 92.6.550-555).
The Wessels Mine, Hotazel, Kalahari manganese field, Northern Cape, South Africa, is the source of the finest
sugilite worldwide, both in massive form and crystallised. Associated
minerals include wollastonite,
pectolite, johannsenite,
quartz, richterite,
andradite and
hydroxyapophyllite.
One sample has been found of sugilite with quartz,
pectolite and strontianite
(R&M 92.6.550-555).
At the N'Chwaning III Mine, N'Chwaning Mines, Kuruman, Kalahari manganese field, Northern Cape, South Africa, fibrous
sugilite has been found associated with lipuite
and taniajacoite on an oxidised
manganese ore matrix
(R&M 92.6.550-555).
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