General Information:
Chemical Formula:
(Sc,Y)2Si2O7
Composition:
(Molecular Weight = 280.05 gm)
Yttrium 15.87 % Y
Scandium 24.08 % Sc
Silicon 20.06 % Si
Oxygen 39.99 % O
Empirical Formula:
Sc1.5Y0.5Si2O7
Environment:
Granitic pegmatite rocks.
Locality:
Iveland, Setesdal, Norway.
Name Origin:
Named after the Norwegian engineer, O. Thortveit.
Physical Properties:
Cleavage:
[100] Perfect
Color:
brown, grayish black, black, or grayish green.
Density:
3.5
Diaphaniety:
Translucent to opaque
Habits:
Crystalline - Fine - Occurs as well-formed fine sized crystals., Radial - Crystals radiate from a center without producing stellar forms (e.g. stibnite), Prismatic - Crystals Shaped l ike Slender Prisms (e.g. tourmaline).
Hardness:
6.5 - Pyrite
Luminescence:
Non-fluorescent.
Luster:
Vitreous - Adamantine
Streak:
gray
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