Actinolite Value, Price, and Jewelry Information
Actinolite is a member of a series that contains varying amounts of iron and magnesium.
1 Minute Read
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.
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 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. 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. joelarem.com
Related Articles
Faceting Tips for Exotic Gemstones
Black Diamond Value, Price, and Jewelry Information
Chameleon Diamond Value, Price, and Jewelry Information
Gray Diamond Value, Price, and Jewelry Information
Latest Articles
A Guide to Early Victorian Romantic Period Jewelry
Malaya or Malaia Garnet Value, Price, and Jewelry Information
Choosing Your First Gemstones: A Rough Guide for Faceters
Gemstone Coatings: CVD and More
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!