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.
1 Minute Read
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.
Start an IGS Membership today
for full access to our price guide (updated monthly).Actinolite Value
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 |
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.
Related Articles
Faceting Tips for Exotic Gemstones
Calcite Value, Price, and Jewelry Information
Brucite Value, Price, and Jewelry Information
Chicken-Blood Stone Value, Price, and Jewelry Information
Never Stop Learning
When you join the IGS community, you get trusted diamond & gemstone information when you need it.
Get Gemology Insights
Get started with the International Gem Society’s free guide to gemstone identification. Join our weekly newsletter & get a free copy of the Gem ID Checklist!