General Information:
Chemical Formula:
Ca5(SiO4,PO4,SO4)3(F,OH,Cl)
Composition:
(Molecular Weight = 503.55 gm)
Calcium 39.80 % Ca
Silicon 5.58 % Si
Phosphorus 6.15 % P
Hydrogen 0.06 % H
Sulfur 6.37 % S
Chlorine 0.70 % Cl
Oxygen 39.08 % O
Fluorine 2.26 % F
Empirical Formula:
Ca5(SiO4)(PO4)(SO4)F0.6(OH)0.3Cl0.1
Environment:
Contact metamorphic skarn.
IMA Status:
Approved IMA
Locality:
Crestmore, Riverside, California, USA.
Name Origin:
Named for the composition and Reuben B. Ellestad (1900-1993), Amierican analytical chemist of Minneapolis, Minnesota, USA.
Physical Properties:
Cleavage:
None
Color:
blue, pale bluish green, or colorless.
Density:
3.03 - 3.07, Average = 3.05
Diaphaniety:
Transparent to Translucent
Habits:
Massive - Uniformly indistinguishable crystals forming large masses., ,
Hardness:
4.5 - Between Fluorite and Apatite
Luminescence:
Sometimes Fluorescent, Short UV=bluish white, Long UV=weak white.
Luster:
Vitreous - Greasy
Streak:
bluish white
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