Chabazite: Nova Scotia (specimen ~ 3 inches across). Photo © Joel E. Arem, PhD, FGA. Used with permission.
Although faceting chabazite isn’t too difficult, it’s too soft for jewelry. However, only a handful of cut chabazites may exist because facetable material is extremely scarce.
| Data | Value |
|---|---|
| Name | Chabazite |
| Crystallography | Hexagonal. Crystals rhomb-shaped, tabular; frequently twinned. |
| Crystallographic Forms | |
| Refractive Index | 1.470-1.494 |
| Colors | Colorless, white, yellowish, pinkish, reddish white, salmon color, greenish. |
| Hardness | 4-5 |
| Fracture | Uneven |
| Cleavage | Distinct 1 direction |
| Luminescence | None |
| Luminescence Present | No |
| Absorption Spectrum | Not diagnostic. |
| Formula | CaAl2Si4O12 · 6H2O |
| Optics | Variable; RI = 1.470 - 1.494. Uniaxial (+) or (-). See “Identifying Characteristics” below. |
| Optic Sign | Uniaxial +, Uniaxial - |
| Etymology | Originally named chabasie by Bosc d'Antic in 1780, later changed to chabazite. See “Comments” below. |
| Occurrence | Cavities in basalt and other basic igneous rocks; also hot spring deposits. |
| Luster | Vitreous. |
| Specific Gravity | 2.05-2.16 |
| Transparency | Transparent to translucent. |
| Birefringence | 0.024 |
| Pleochroism | None. |
Salmon-pink “Chabazite on Heulandite,” Upper Quarry, New St., Paterson, New Jersey, USA. © Rob Lavinsky, www.iRocks.com. Used with permission.
Chabazite refers to a series of related minerals. This series include calcium (Ca), potassium (K), magnesium (Mg), sodium (Na), and strontium (Sr) dominant members. The sodium-dominant member is also known as herschelite.
This stone can show pale but attractive colors. Unfortunately, it’s too soft to wear (hardness 4 – 5) and rarely found in clean condition. Usually, faceters can cut only one corner of pinkish or colorless crystals, since they’re never entirely transparent. Even museum collections seldom possess cut material.
This rare, relatively little-known gem has a poetic but mangled etymology. The name “chabazite” comes from a poem attributed to the poet Orpheus from Greek mythology. However, the actual source, the 4th century CE Orphic Lithica of Pseudo-Orpheus, refers to chalazias, a stone said to be like hail. According to this mystical work, the stone purportedly cooled passions and cured fevers and snakebites. Evidently, its magical purview doesn’t include typos. The “b” in the modern name came from a misspelling in a text of the poem used in the 18th century.
What was chalazias? Possible identities for this gem range from quartz to diamond. Chabazites have been found in Greece, Cyprus, and the Aegean region, too.
Chabazite’s optic sign may vary. It may be uniaxial positive or negative.
Phacolite is a lens-shaped variety of chabazite. These form due to twinning/multiple twinning of rhombohedrons, shapes hexagonal or trigonal crystal structures may take. “Chabazite (Var. Phacolite),” Gads Hill, Upper Mersey Valley, Tasmania, Australia. © Rob Lavinsky, www.iRocks.com. Used with permission.
Labs have created synthetic minerals, like SSZ-13, isostructural with chabazite. (They share the same crystal structure but not the same chemical composition). These materials only have industrial uses.
Cut chabazites are always very small, usually less than 1-2 carats.
You’re more likely to find chabazites in mineral collections, if at all, than in jewelry collections. These gems have significantly lower hardness than common jewelry stones, such as quartz and topaz, not to mention diamond. Therefore, store them separately from other gems to avoid contact scratches. For cleaning, use a soft brush, mild detergent, and warm water. Consult our gemstone jewelry cleaning guide for more recommendations.
“Chabazite,” Wadamana, Central Tasmania. © Rob Lavinsky, www.iRocks.com. Used with permission.
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