Actinolite Value, Price, and Jewelry Information

Actinolite

Actinolite

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 Value

The International Gem Society (IGS) has a list of businesses offering gemstone appraisal services.

Actinolite Value via Gem Price Guide

Accompanying value information:
Not found
Cut Weight Price
Cat’s Eye 1 carat /ct

Actinolite Information

Data Value
Name Actinolite
Varieties Smaragdite
Colors Pale to dark green, blackish green, black.
Hardness 5.5
Fracture Uneven, Often fibrous nature
Cleavage 2 directions good
Stone Sizes Actinolite is rarely facetable and usually in small fragments. Material from Chester, Vermont, could provide stones to about 10 carats. DG: 2.06 (greenish, step cut, Africa)
Formula Ca2(Mg, Fe)5Si8O22(OH)2
Crystallography Monoclinic; bladed crystals, usually elongated; fibrous, columnar aggregates. Also massive, granular, Often twinned.
Refractive Index 1.619-1.644
Birefringence 0.022-0.026.
Dispersion 0.009
Luminescence None (due to presence of Fe).
Absorption Spectrum Faint line at 5030.
Pleochroism

Yellow to dark green. Material transparent to nearly opaque. α: pale yellow/ yellowish-green. β: pale yellow-green/green. γ: pale green/ deep greenish blue.

Optics α = 1.619-1.622; β = 1.632-1.634; γ = 1.642-1.644 (Tanzanian material). Biaxial (-); 2V = 78°. See chart for series member optics.
Optic Sign Biaxial -
Luminescence Present No
Luster Vitreous, sometimes dull.
Specific Gravity Usually 3.05; Tanzania: 3.03-3.07; Max.: 3.44.
Transparency Translucent to transparent.
Phenomena Chatoyancy.

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.

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.)

Enter your email to access the Ultimate Opal Buying Guide for free!

FREE

THANK YOU!

 

PLEASE CHECK YOUR EMAIL FOR THE E-BOOK

Follow us on Facebook