Formula: Ca5(SiO4)1.5(SO4)1.5F
Nesosilicate (insular SiO4 groups)
Specific gravity: 3.03
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

Metamorphic environments
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).


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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