Boracite Value, Price, and Jewelry Information

Light bluish green boracite, 0.33 cts, 4.3 mm, square cut, Lower Saxony, Germany. © The Gem Trader. Used with permission.

Boracite

With light blue and green colors, no cleavage, and high hardness, boracite is an uncommon mineral. Unfortunately for jewelry lovers, faceted boracites are very rare.

Boracite Information

Data Value
Name Boracite
Colors Colorless, white, gray, orange, yellow, pale to dark green, bluish green, pink (very rare).
Crystallography Orthorhombic. Pseudo-tetragonal. Crystals small and equant.
Refractive Index 1.658-1.673
Luster Vitreous.
Hardness 7-7.5.
Wearability Good
Fracture Conchoidal to uneven
Specific Gravity 2.95
Birefringence 0.010-0.011
Cleavage None
Dispersion 0.024
Luminescence Weak greenish (SW)
Luminescence Present Yes
Luminescence Type Fluorescent, UV-Short
Transparency Translucent to transparent.
Absorption Spectrum Not diagnostic.
Formula

Mg3B7O13Cl

Pleochroism

None.

Optics

α = 1.658-1.662; β = 1.662-1.667; γ = 1.668-1.673. Biaxial (+), 2V =82°.

Optic Sign Biaxial +
Etymology

Named after the boron in its composition.

Occurrence

Secondary deposits formed in evaporite sequences (seawater).

boracite - type locality

Boracite, Kalkberg Hill, Luneburg, Lower Saxony, Germany, (type locality). © Rob Lavinsky, www.iRocks.com. Used with permission.

boracite - England

Aqua-colored boracites, crystals about 2 mm across, specimen 5.8 x 3.2 x 1.8 cm. Boulby Mine, Loftus, North Yorkshire, England, UK. © Rob Lavinsky, www.iRocks.com. Used with permission.

Comments

Boracite forms in salt deposits and similar environments as a result of seawater evaporation in enclosed basins. Rare cut boracites can show delicate shades of blue, green, yellow, white, and grey and have moderate dispersion. Some stones are colorless.

boracite - 0.21 cts

Boracite, 0.21 cts. Photo © Joel E. Arem, PhD, FGA. Used with permission.

Identifying Characteristics

Under physical pressure, boracite generates an electric charge. This is known as known the piezoelectric effect. This mineral also exhibits the pyroelectric effect. It generates an electric charge when heated.

Boracites decompose slowly in water.

Synthetics

Scientists have synthesized boracites for various purposes, including research into its electrical properties as well as radioactive waste storage. However, there’s no known jewelry use for this synthetic material.

Sources

Cuttable crystals occur only in the Stassfurt and Hanover districts of Germany, which usually yield small, pale crystals.

Other notable gem sources include the following:

  • United States: Otis, California; Choctaw Salt Dome, Louisiana.
  • England: North Yorkshire, Aislaby.
  • Bolivia; Canada; China; France; Kazahkstan.
boracite - pink

This boracites on matrix specimen contains pale blue-gray crystals as well as a single, rare orange-pink crystal. Alto Chapare District, Chapare Province, Cochabamba Department, Bolivia. © Rob Lavinsky, www.iRocks.com. Used with permission.

Stone Sizes

Boracite crystals are very small and usually yield gemstones ranging from 1-2 carats, so gems over 2 carats would be considered extreme rarities.

Care

Although boracites react to water very slowly, keep them dry in storage, where they would otherwise have time to sit and decompose. Alcohol may be used in lieu of water for cleaning. Otherwise, since these stones have high hardness (7-7.5) and no cleavage, they require no special care. Consult our gemstone jewelry cleaning guide for more recommendations.

faceted boracite - Germany

Boracite: Hanover, Germany (0.6). © Joel E. Arem, PhD, FGA. Used with permission.

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