Actinolite
Actinolite

Actinolite Value, Price, and Jewelry Information


Actinolite is a member of a series that contains varying amounts of iron and magnesium. Tremolite is the Mg end, and ferroactinolite the Fe end, with actinolite in the middle. Actinolites with more than 50% Fe are very rare. Catseye actinolite exists (S.G. 3.0, R.I. 1.63); when chatoyant material is cut, it exhibits a fine eye. Actinolite is easy to cleave and hard to cut and would make a poor jewelry stone. Actinolite is the chief constituent of nephrite (jade). Smaragdite is a chrome-rich tremolite from Tanzania.

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Actinolite is a member of a series that contains varying amounts of iron and magnesium. Tremolite is the Mg end, and ferroactinolite the Fe end, with actinolite in the middle. Actinolites with more than 50% Fe are very rare. Catseye actinolite exists (S.G. 3.0, R.I. 1.63); when chatoyant material is cut, it exhibits a fine eye. Actinolite is easy to cleave and hard to cut and would make a poor jewelry stone. Actinolite is the chief constituent of nephrite (jade). Smaragdite is a chrome-rich tremolite from Tanzania.

Actinolite
Actinolite

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Actinolite Value

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Comments: Actinolite is a member of a series that contains varying amounts of iron and magnesium. Tremolite is the Mg end, and ferroactinolite the Fe end, with actinolite in the middle. Actinolites with more than 50% Fe are very rare. Catseye actinolite exists (S.G. 3.0, R.I. 1.63); when chatoyant material is cut, it exhibits a fine eye. Actinolite is easy to cleave and hard to cut and would make a poor jewelry stone. Actinolite is the chief constituent of nephrite (jade). Smaragdite is a chrome-rich tremolite from Tanzania.

Name: Greek aktis, meaning ray, due to the fibrous nature.

Optics:

α = 1.619-1.622;

β = 1.632-1.634;

γ = 1.642-1.644 (Tanzanian material).

Biaxial (-); 2V = 78°

Occurrence: Contact metamorphic limestones and dolomites; magnesium-rich limestones and ultrabasic rocks; regionally metamorphosed rocks.

LocalityPleochroic ColorsαβγBirefringenceS.G.Comments
Fowler, New Yorkred-violet1.602-1.6300.0283.03Hexagonite
Kenyabright green1.6021.6131.6280.0262.99Tremolite
1.6071.6181.6320.0253.01
Tanzania (Lelatema)yellow green/green1.6081.6161.6310.0233.01Tremolite
Tanzaniaemerald green1.6111.6231.6390.0283.30Tremolite + Cr
Tanzania (Merelani)yellow-green/emerald green1.6081.6181.630.022Smaragdite
Taiwanyellow-green/green tones,1.607--1.630-0.023-3.01Tremolite
also brownish1.6091.6330.024
1.615--1.631-0.014-3.01Catseye tremolite
1.6191.6330.016
Ugandayellow-green/green1.619-1.632-1.642-0.021-3.04-Tremolite-Actinolite
1.6221.6341.6440.0243.07
green/brown1.633-1.6530.0203.15Actinolite
Chemical composition vs. optics and density of common hornblendes. Adapted from W.A. Deere, R.A. Howie, and J. Zussman, 1962, The Rock Forming Minerals, vol.2 (New York: Wiley), p.296.
Chemical composition vs. optics and density of common hornblendes.
Adapted from W.A. Deere, R.A. Howie, and J. Zussman, 1962, The Rock Forming Minerals, vol.2 (New York: Wiley), p.296.

Chester, Vermont.

Madagascar: small, dark green crystals. Many of these are clean and suitable for faceting.

Tanzania: transparent crystals. (See also nephrite.)


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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