Actinolite Actinolite

Actinolite Value, Price, and Jewelry Information


Actinolite is a member of a series that contains varying amounts of iron and magnesium.

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Home Gemstones Actinolite Value, Price, and Jewelry Information

Actinolite is a crystal found in countries like the US, Brazil, China, and Canada. Actinolite is commonly used in industrial applications such as in the production of asbestos because it has similar properties to asbestos fibers. It is sometimes used as a gemstone, but it is not suitable for jewelry. Some types of actinolite are rare, which makes it an attractive to some collectors.

Actinolite
This a faceted, natural, green actinolite.

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Actinolite Value

1 carat
Cat's Eye
/ct

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Comments: Actinolite is a member of a series that contains varying amounts of calcium, magnesium, iron, and aluminum, and has a chemical formula of Ca2(Mg,Fe)5Si8O22(OH)2. Tremolite is the Mg end, and ferroactinolite the Fe end, with actinolite in the middle. Actinolites with more than 50% Fe are very rare. Catseyeactinolite 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).Smaragditeis a chrome-rich tremolite from Tanzania.

Name:Greekaktis,meaningray,due to the fibrous nature.

Optics:

α  = 1.619-1.622;

β = 1.632-1.634;

γ = 1.642-1.644 (Tanzanian material).

Biaxial (-); 2 V = 78°

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

Locality Pleochroic Colors α β γ Birefringence S.G. Comments
Fowler, New York red-violet 1.602 - 1.630 0.028 3.03 Hexagonite
Kenya bright green 1.602 1.613 1.628 0.026 2.99 Tremolite
1.607 1.618 1.632 0.025 3.01
Tanzania (Lelatema) yellow green/green 1.608 1.616 1.631 0.023 3.01 Tremolite
Tanzania emerald green 1.611 1.623 1.639 0.028 3.30 Tremolite + Cr
Tanzania (Merelani) yellow-green/emerald green 1.608 1.618 1.63 0.022 Smaragdite
Taiwan yellow-green/green tones, 1.607- - 1.630- 0.023- 3.01 Tremolite
also brownish 1.609 1.633 0.024
1.615- - 1.631- 0.014- 3.01 Catseye tremolite
1.619 1.633 0.016
Uganda yellow-green/green 1.619- 1.632- 1.642- 0.021- 3.04- Tremolite-Actinolite
1.622 1.634 1.644 0.024 3.07
green/brown 1.633 - 1.653 0.020 3.15 Actinolite
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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