Sarcolite: Italy (0.33). Photo © Joel E. Arem, PhD, FGA. Used with permission.
Sarcolite
Sarcolite is an extremely rare mineral. Tiny, colorless to “fleshy pink” gems have been cut only from material from one locality: Mount Vesuvius.
Sarcolite Information
| Data | Value |
|---|---|
| Name | Sarcolite |
| Crystallography | Tetragonal. Crystals equant, grains. |
| Refractive Index | 1.604-1.657 |
| Colors | Colorless, reddish, rose red, reddish white, "fleshy pink." |
| Hardness | 6 |
| Fracture | Conchoidal. |
| Birefringence | 0.011-0.017 |
| Cleavage | None. |
| Formula | (Ca,Na)4Al3(Al,Si)3Si6O24 |
| Optics | o = 1.604-1.640; e = 1.615-1.657. Uniaxial (+). |
| Optic Sign | Uniaxial + |
| Etymology | From the Greek words for "flesh" and "stone," in allusion to the color. |
| Occurrence | In contact metamorphosed limestone-bearing volcanic ejecta. |
| Luster | Vitreous. |
| Specific Gravity | 2.92 |
| Transparency | Translucent. |
Sarcolite crystal. Collected from Mount Vesuvius, Italy by William Thomson. From the collection of the National Museum of Scotland. Photo by Geni. Licensed under CC By-SA 3.0.
Synthetics
Researchers have synthesized sarcolites with the same chemical formula and tetragonal crystal structure as their natural counterparts. However, this lab-created material has different optical properties: o = 1.631; e = 1.615; uniaxial (-).
There is no known jewelry use for this synthetic material.
Enhancements
No known gemstone treatments.
Sources
Sarcolite’s type locality is the volcanic rock of Mt. Vesuvius (Monte Somma) in the region of Campania in southern Italy. Other Italian sources include Rome and the province of Trentino in northern Italy.
Connecticut and Nevada in the United States also produce sarcolite.
Stone Sizes
All faceted stones weigh 1-2 carats or less.
Care
You’ll likely find sarcolites only in very complete mineral collections, if at all. Although this stone has a mid-range Mohs hardness of 6 and no cleavage, it also has “very brittle” tenacity. This means sarcolite has greater susceptibility to damage from blows than most other gemstones, common or rare. If worn as jewelry, make sure these stones have protective settings and reserve them for occasional wear.
Consult our gemstone jewelry cleaning guide for more recommendations.
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