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Formula: Ca5(SiO4)1.5(SO4)1.5F
Nesosilicate (insular SiO4 groups), ellestadite group,
apatite supergroup
Crystal System: Hexagonal
Specific gravity: 3.03 measured, 3.090 calculated
Hardness: 4½
Streak: White with a weak bluish tint
Colour: Blue to pale bluish, light rose-red, yellow
Solubility: Soluble and weakly effervescent in hydrochloric acid, leaving a silica residuum that retains the original form
(Mindat)
Common impurities: Al,Fe,Mn,Mg,Na,K
Environments
Metamorphic environments
Coal-seam fires
Burnt petrified wood
Fluorellestadite is a relatively rare mineral found in contact
metamorphic skarn or metamorphosed
limestone. It is also known from burned coal dumps (Mindat). Associated
minerals include periclase, magnesioferrite,
hematite, srebrodolskite and
anhydrite
(HOM).
Localities
There are two co-type localities, Coal mine No. 44, Kopeysk, Chelyabinsk Oblast, Russia, and the Crestmore quarries, Crestmore,
Riverside county, California, USA.
At Mapimi, Mexico, fluorellestadite pseudomorphs after
hematite have been found
(KL p222).
At Coal mine No. 44, Kopeysk, Chelyabinsk Oblast, Russia, fluorellestadite was found in burned fragments of petrified wood
in coal dumps, associated with lime, periclase,
magnesioferrite, hematite,
srebrodolskite, anhydrite and
anhydrous lime silicates
(AM 74.502-503, HOM).
At the Commercial quarry, Crestmore, Riverside county, California, USA, fluorellestadite has been found in blue
calcite
(KL p222).
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