Xonotlite Value, Price, and Jewelry Information

Faceted xonotlite (about 2 carats): Laghi di Posina, Vicenza, Italy. Photo © Joel E. Arem, PhD, FGA. Used with permission.

Xonotlite

Xonotlite is strong and can take a good polish. However, these gems are extremely rare, both as a species and cut specimens.

Xonotlite Information

Data Value
Name Xonotlite
Crystallography Monoclinic: crystals acicular; usually massive, fibrous, or compact.
Refractive Index 1.583-1.593
Colors Chalky white to colorless, pink, light to medium gray.
Luster Greasy; pearly; dull vitreous.
Hardness 6
Fracture Splintery
Specific Gravity 2.71
Birefringence 0.010
Cleavage Good in one direction
Luminescence None reported.
Luminescence Present No
Transparency Transparent to translucent.
Absorption Spectrum None.
Formula Ca6Si6O17(OH)2
Pleochroism None.
Optics a = 1.583; β = 1.583; γ = 1.593. Biaxial (+).
Optic Sign Biaxial +
Etymology After the type locality, Tetela de Xonotla, Mexico.
Occurrence Typically as veinlets in serpentine or in contact zones.
xonotlite, selenite, and inesite

“Like a fly trapped in amber,” notes Rob Lavinsky, an ivory-colored xonotlite sphere lies within a layer of selenite. Other xonotlites and a red inesite appear on the surface. Xonotlites, selenite, and inesite, 4.8 x 4.2 x 2.2 cm, Wessel’s Mine, Kalahari Manganese Fields, South Africa. © Rob Lavinsky, www.iRocks.com. Used with permission.

Comments

Lapidaries have cut translucent (not truly transparent) faceted stones up to several carats in size from Italian material.

Synthetics

Researchers have synthesized xonotlite via the hydrothermal method. The synthetic material has been used in powder form for industrial purposes, such as absorption, insulation, and pigment extension. However, no jewelry use for this material is known.

xonotlite - fibrous mass, Italy

Although xonotlite crystals can take acicular (needle-like) forms, like these specimens from Vicenza, Veneto, Italy, this material usually occurs as fibrous masses. Researchers who synthesize this mineral take particular interest in this fibrous property. Photo by Aangelo. Licensed under CC By-SA 3.0.

Enhancements

None known.

Sources

Mexico and the Vicenza region of Italy have produced gem-quality, facetable material.

  • Tetela de Xonotla, Mexico.
  • Laghi di Posina, Vicenza, Italy.
emerald-cut xonotlite - Italy

Emerald-cut xonotlite (about 2 carats): Laghi di Posina, Vicenza, Italy. Photo © Joel E. Arem, PhD, FGA. Used with permission.

Other notable sources include the following:

  • United States: California; Michigan; Puerto Rico; Virginia.
  • Canada; Japan; South Africa.

Care

Despite a mid-range hardness (6), xonotlites have greater resistance to blows than many jewelry gemstones. They have a “tough” tenacity, while most gemstones only rank as “brittle.” Nevertheless, you’re more likely to find these stones in mineral collections than in jewelry collections. Consult our gemstone jewelry cleaning guide for care recommendations.

xonotlite -South Africa

The “broken” sphere of one of the xonotlite crystals in this specimen shows how this gem’s acicular crystal formations create these spherical aggregates. Xonotlites, Wessel’s Mine, Hotazel, Kalahari manganese fields, Northern Cape Province, South Africa. © Rob Lavinsky, www.iRocks.com. Used with permission.

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