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Schorl

UNB-2017-0001Minerals » Silicates » Cyclosilicates

Description

Sample of short prismatic black Schorl euhedral crystals with some visible striations entwined with colourless prismatic subhedral Quartz crystals. Lustre is vitreous for the Schorl crystals and greasy for the Quartz crystals. Average Schorl crystal size: 0.7 cm x 0.7 cm x 0.3 cm. Schorl (Na(Mg,Fe)3Al6(BO3)3(Si6O18)(OH,F)4) is the common name for Black Tourmaline and has a vitreous lustre and a white streak. Hardness is 7 to 7 1/2. Tourmaline usually occurs as long or short prismatic crystals that have striations on the length of the crystal faces. Schorl can also be radial, columnar and compact. Cross-section shows a rounded triangular.

Specifications

Object nameSchorl
IDUNB-2017-0001
Legal statusPermanent collection
CategoryMineral
Classification
Mineral group:
Silicates
Sub-group:
Cyclosilicates
Composition
  • BaTiSi3O9
  • (Mg,Fe)2Al3(Si5AlO18)
  • (Ca,Fe,Mg)3Al2BO3Si4O12(OH)
  • Be3Al2(Si6O18)
  • Be3Al2(Si6O18)
  • Na(Li,Al)3Al6(BO3)3Si6O18(OH)4
  • Na15Ca6(Fe2+,Mn2+)3Zr3Si25O733(CO3)
  • (Ca,Na)19(Al,Mg,Fe)13(SiO4)10(Si2O7)4(OH,F,O)10
  • (Na,Ca)(Fe,Mg,Li,Al)3Al6(BO3)3(Si6O18)(OH)4
  • Be₃Al₂(SiO₃)₆
  • A(D3)G6(T6O18)(BO3)3X3Z
OriginUnknown
Pieces1
PartialNo
Measurements
  • 11cm x 12cm x 9cm

Publications

  • Chesterman, C.W. 1979. Audubon Society, Field Guide to North American Rocks and Minerals. Knopf.