Mineral description : Schorl

Schorl crystals in quartz from Hemavan.
Terminated schorl crystal from Kaatiala, Finland.
Schorl crystals in quartz from Mossbodarna.

Mineral class Silicates : Cyclosilicates : Beryl - Tourmaline group.
Chemical formula (Na,Ca)(Fe,Mg,Al,Mn,Li)3Al6(BO3(OH,F)4(Si6O18)
Crystal system Trigonal / Hexagonal.
Habitus As rounded triangular striated crystals. Often as hexagonal crystals. Commonly as radiating aggregates. Also in compact and massive habitus.
Cleavage Very indistinct, basally partening, fracture uneven to conchoidal.
Hardness 7-7.5
Density 3-3.2
Color Black.
Streak Colorless.
Luster Vitreous, opaque.
Description The most commonly tourmaline mineral. Schorl is the iron rich member of the tourmaline family.
Occurance Pegmatites and granites, also in some metamorphic rock.
Associates Beryl, Zircon, Quartz, Feldspar, mica minerals.
Notes Insoluble in acids.
Harder to fuse than the elbaites.
Locations A common mineral in pegmatites all over Sweden.
  • Skrumpetorp feldspar quarry, Godegård, Östergötland. As crystals up to 3x1m.
  • Västerby quartz quarry, Östergötland. Commonly with crystals up to a couple of dm in length.
  • Käringbricka quartz quarry, Västerfärnebo, Västmanland. Commonly of short triangular crystals in gabbro pegmatite.
  • Mossbodarna quartz quarry, Överhogdal, Härjedalen. Commonly of radiating groups of schorl in rose quartz.
  • Råneå quartz quarry, Norrbotten. As crystals up to 50 cm in quartz and feldspar.
  • Varuträsk, Västerbotten. As crystals and crystal fragments in the borderzone of the pegmatite.
  • Kaatiala, Finland. As big crystals in quartz and feldspar.

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Last changed : 1998-05-04