Tremolite Value, Price, and Jewelry Information


It is possible to misidentify tremolite, mistaking it for other amphiboles. Hexagonite is the rarest of the gem varieties of tremolite. If tremolite occurs in very tiny fibrous crystals, densely matted and interlocked, it is then known as nephrite (jade). Material containing more or less parallel fibers is somewhat chatoyant and yields weak catseyes. These are sometimes called catseye jades, but have been tested and are actually tremolite or (if more iron-rich) actinolite.

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TREMOLITE: Hexagonite, Balmite, New York (~1, crystal ~ 1 inch long). Photo © Joel E. Arem, PhD, FGA. Used with permission.

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Tremolite Value

Highest values go to faceted gems, particularly Hexagonite and chrome Tremolite, and strong cats eyes.

Optics

a =1.560-1.562; β= 1.613; γ=1-624-1.643

Biaxial (-), 2V= 81°.

Note: Tanzania, green crystals: 1.608-1.631, S.G. 3.02.

Occurrence

Tremolite occurs in contact and regionally metamorphosed dolomites, in magnesian limestones, and in ultrabasic rocks.

  • California; Arizona; Utah; Colorado; Connecticut; South Dakota; Massachusetts.
  • Italy; Switzerland; Austria.
  • Fowler, New York: hexagonite, some cuttable; also at Edwards and Balmat, New York.
  • Ontario and Quebec, Canada: gray, green and blue crystals; a chatoyant greenish variety found in Ontario cuts interesting catseye gems.
  • Burma: green catseye gems.
  • Lelatemu,Tanzania: green facetable crystals up to 25mm.
  • Sierra Leone: Cr-rich tremolite, deep green with Cr spectrum displayed.

Comments

It is possible to misidentify tremolite, mistaking it for other amphiboles. Hexagonite is the rarest of the gem varieties of tremolite. If tremolite occurs in very tiny fibrous crystals, densely matted and interlocked, it is then known as nephrite (jade). Material containing more or less parallel fibers is somewhat chatoyant and yields weak catseyes. These are sometimes called catseye jades, but have been tested and are actually tremolite or (if more iron-rich) actinolite.

Name

From the Tremola Valley on the south side of St. Gotthard, Switzerland. Hexagonite was so named because it was thought to be a hexagonal mineral when first described.

Variety Names

 Hexagonite, purple Tremolite

 


Joel E. Arem, Ph.D., FGA

Dr. Joel E. Arem has more than 60 years of experience in the world of gems and minerals. After obtaining his Ph.D. in Mineralogy from Harvard University, he has published numerous books that are still among the most widely used references and guidebooks on crystals, gems and minerals in the world.

Co-founder and President of numerous organizations, Dr. Arem has enjoyed a lifelong career in mineralogy and gemology. He has been a Smithsonian scientist and Curator, a consultant to many well-known companies and institutions, and a prolific author and speaker. Although his main activities have been as a gem cutter and dealer, his focus has always been education. joelarem.com

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