Epidote Value, Price, and Jewelry Information
The epidote mineral supergroup contains many related species of interest to collectors. However, epidote itself is the one most likely to be faceted into beautiful, albeit small and dark, gemstones.
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The epidote mineral supergroup contains many related species of interest to collectors. However, epidote itself is the one most likely to be faceted into beautiful, albeit small and dark, gemstones.
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What is Epidote?
Although epidotes have loaned their name to the epidote mineral supergroup, the gems themselves form a clinozoisite-epidote solid-solution series within this taxon.
Is Tanzanite an Epidote?
In 2006, mineralogists removed all varieties of zoisite, including its most well-known member, tanzanite, from the epidote supergroup. Zoisite is an orthorhombic polymorph of monoclinic clinozoisite. Mineralogists reclassified zoisite since all other epidote members had monoclinic crystal systems.
Does Epidote Make a Good Jewelry Stone?
Despite losing tanzanite, the epidote supergroup still includes some interesting gemstones, both common and rare. It features species suitable for faceting and cabbing as well as beautiful crystals for collecting. These materials often contain fibrous inclusions. On rare occasions, they create a chatoyant "cat's eye" effect in cabbed epidotes and clinozoisites.
Some epidotes may have a hardness of 7, on par with quartz. However, most gem materials in this supergroup have a hardness of 6 or softer. Since these gems also have perfect cleavage and sensitivities to heat and acids, they require special care as jewelry stones. Have these stones set in protective settings, especially for ring use, and reserve them for occasional wear.
Epidote Varieties
Epidote
Usually so dark in color, large faceted epidotes result in nearly black, lifeless gems. However, small stones, under 3 to 4 carats, can often turn out as bright and lively faceted gems.
Pistazite or pistacite is a trade name for yellowish green "pistachio-colored" epidote.
Clinozoisite
These gems would actually make better looking faceted pieces than epidotes. Although clinozoisites aren't rare, they occur rarely in sizes over 5 carats.
Some localities occasionally yield fine gems, but clinozoisite rarely occurs in pure form. It usually contains some iron, like its series brother, epidote. Clinozoisite shares a chemical formula and outward appearance (but not a crystal system) with zoisite.
Allanite
Very dark in color and seldom cut, allanite contains rare-earth and radioactive elements. As a result, these gems become metamict. In other words, they have severe damage to their internal crystalline structure.
Hancockite
This New Jersey gemstone is very rare. Faceted pieces, if any exist, would weigh under 1 to 2 carats.
Mukhinite
This very rare mineral occurs in small grains. First discovered in Gornaya Shoriya, Russia, no cut specimens exist.
Piedmontite
Also known as piemontite, this species is sometimes confused with thulite, a pink manganiferous variety of zoisite. While thulite sometimes appears bright pink, piedmontite typically has a dark brown or reddish color. Thulite can occur in large pieces, but piedmontite seldom occurs in large masses. However, both materials can make lovely cabochons.
Tawmawite
A very rare, deep emerald-green colored variety of epidote from Myanmar, this material gets its color from chromium.
Unakite
A popular material for cabochons, unakite, an altered granite, contains green epidote, white to gray quartz, and pink feldspar (orthoclase). The United States produces and exports this widely used lapidary rock, but Ireland, Zimbabwe, and other countries also produce similar material.
Other Lapidary Materials
The light, striped lines of "Zebra Stone" from Arizona may contain epidote.
"Rosalinda," an ornamental rock from Peru, consists of calcite, scapolite, and red epidote-piedmontite.
Another ornamental rock used for carving, "Bowesite," from Australia, consists of epidote, diopside, grossular garnet, actinolite, and other gem materials.
"Lapis Nevada" consists of pink thulite, yellow-green epidote, green diopside, and white to lavender scapolite.
Identifying Characteristics of Epidote
Optics and Specific Gravity
| Clinozoisite | Epidote | Piedmontite | Hancockite | Allanite | |
| Specific Gravity | 3.21-3.38 | 3.38-3.49 | 3.45-3.52 | 4.03 | 3.4-4.2 |
| Optics | |||||
| a | 1.670-1.715 | 1.715-1.751 | 1.732-1.794 | 1.788 | 1.640-1.791 |
| β | 1.675-1.725 | 1.725-1.784 | 1.750-1.807 | 1.81 | 1.650-1.815 |
| γ | 1.690-1.734 | 1.734-1.797 | 1.762-1.829 | 1.83 | 1.660-1.828 |
| 2V | (+) 14-90° | (-) 90-116° | (+) 2-9° | (-) 50° | (+/-) 40-123° |
| Birefringence | 0.005-0.015 | 0.015-0.049 | 0.025-0.073 | 0.042 | 0.013-0.036 |
Sri Lanka produces a yellow-brown epidote with the following properties:
- Specific Gravity: 3.33
- Pleochroism: yellow-green/brown/greenish-yellow.
- Optics: a = 1.718; β = 1.734; γ = 1.738.
- Birefringence: 0.020.
Minas Gerais, Brazil produces cuttable, yellowish-green trichroic crystals. They're low in iron and have the following properties:
- Specific Gravity: 3.30 - 3.50
- Optics: a = 1.722; β = 1.737; y = 1.743.
- Birefringence: 0.021.
Streak
Epidote may have a gray streak. Please note that streak testing may harm or destroy your specimen. Conduct it on a piece of rough, never a finished gem, only as a last resort.
Are There Any Synthetic Epidotes?
Scientists have synthesized epidotes for petrological research. Clinozoisite has also been created for mineralogical research. However, there is no known jewelry use for these materials.
Epidotes don't typically receive any treatments or enhancements.
Where are Epidotes Found?
Epidote Sources
Untersulzbachthal, Austria is the main source of faceting rough.
Other important gem-quality sources include the following:
- Bourg d'Oisans, France: fine crystals.
- Italy: Piedmont, other localities.
- Switzerland: many localities.
- United States: McFall Mine, Ramona, California; Colorado; Connecticut; Idaho; Massachusetts; Michigan; New Hampshire.
- Australia; Brazil; Czech Republic; Japan; Kenya; Madagascar; Baja California, Mexico; Arendal, Norway; Pakistan; Russia; Slovakia; South Korea; Sri Lanka.
- Tawmaw, Myanmar: a chrome-rich material, fine deep green color (tawmawite).
- Outokumpu, Finland: chromiferous epidote (tawmawite).
Clinozoisite Sources
The best known source of gem-quality material, Gavilanes, Baja California, Mexico produces brownish facetable crystals.
Other notable gem-quality sources include the following:
- Kenya: gray-green crystals.
- Austria: Goslerwand, Tyrol (type locality).
- United States: Nevada; Colorado.
- Timmons, Ontario, Canada; Czech Republic; Iceland; India; Ireland; Italy; Pakistan; Slovakia; Switzerland.
Allanite Sources
Various localities throughout the United States produce this material.
Other sources include the following:
- Brazil; Canada; Greenland; Madagascar; Norway; Russia; Sweden.
Hancockite Sources
Franklin, New Jersey, the only notable locality, produces small crystals.
Piedmontite Sources
Piedmontite occurs in sericite schists in Piemonte, Italy. Egypt produces a porphyry colored red by piedmontite. California and Arizona also have many producing localities.
Other sources include the following:
- United States: Missouri; New Mexico; Pennsylvania.
- Morbihan, France; Japan; Otago, New Zealand; Scotland; Vermland, Sweden.
Unakite Sources
Blue Ridge, Unaka Range, North Carolina produces this lapidary material. Other sources include Virginia and Georgia. In addition, Zimbabwe yields a similar rock.
Stone Sizes
Unakite occurs in huge blocks weighing many pounds. Gem cutters often cut it into spheres as well as cabs. Facetable epidote is rare over 5 carat sizes. Cut clinozoisite tends to be even smaller. Allanite is rarely ever cut, except as cabochons. Piedmontite is opaque and massive. It's also cut only as cabochons.
- Smithsonian Institution (Washington, DC): 3.9 (epidote, brown, Austria).
- Devonian Group (Calgary, Alberta, Canada): 7.30 (clinozoisite, brownish, Iran); 6.90 (epidote, brown).
- Private Collection: 15 (clinozoisite, light brown-green, Baja).
How to Care for Epidotes
Clean these gems only with a soft brush, mild detergent, and warm water. For more recommendations, consult our gemstone jewelry care guide.
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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