colemanite - round brilliant cutcolemanite - round brilliant cut

Colemanite Value, Price, and Jewelry Information


Colemanite is an abundant mineral, and transparent material isn’t rare. However, gem cutters rarely facet these typically pale stones. Difficult to cut and wear, colemanites are better suited for collectors of unusual gemstones.

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HomeGemstonesColemanite Value, Price, and Jewelry Information

Colemanite is an abundant mineral, and transparent material isn’t rare. However, gem cutters rarely facet these typically pale stones. Difficult to cut and wear, colemanites are better suited for collectors of unusual gemstones.

colemanite - round brilliant cut
Colorless, round brilliant colemanite, 0.39 cts, 5 mm, Billie Mine, Boron, California. © The Gem Trader. Used with permission.

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Colemanite Value

Colemanite - 26.50 cts
Colemanite: Boron, California (26.50). Photo © Joel E. Arem, PhD, FGA. Used with permission.

Comments

Colemanite serves as an ore for boron and has many industrial uses. As a gemstone, however, it has weak dispersion, so it shows little fire, and normally occurs colorless. Since it also has perfect cleavage and a hardness of only 4.5, this fragile gem would make an unlikely choice for a jewelry stone.

Identifying Characteristics

Colemanites are both pyroelectric and piezoelectric.

  • shield-cut colemanite 1
  • shield-cut colemanite 2
  • shield-cut colemanite 3

    Since colemanite is rarely faceted, its birefringent facet doubling is rarely seen. This large, eye-clean, custom shield-cut specimen displays the effect very nicely. 9.33 cts, 14 x 12.1 mm, Boron, California. © The Gem Trader. Used with permission.

    Synthetics

    Scientists have synthesized colemanites for a variety of research projects, including studies of their electrical properties. However, there's no known jewelry use for this lab-created material.

    Enhancements

    No known gemstone treatments.

    Sources

    The southwestern United States, particularly Boron and Death Valley, California, produces beautiful colemanite crystals. Other notable sources include Argentina, Kazakhstan, and Turkey.

    colemanite crystals - Turkey
    This crystal specimen contains gemmy, honey brown colemanites with "second generation" colorless colemanites on their edges. 5.4 x 5.0 x 3.7 cm, Kestelek Mine, Mustafa Kemalpafla, Bursa Province, Marmara Region, Turkey. © Rob Lavinsky, www.iRocks.com. Used with permission.

    Stone Sizes

    Large crystals and masses could yield gems of 50-100 carats. Crystals normally range up to about 1 inch in size.

    • Smithsonian Institution (Washington, DC): 14.9 (California).

    Care

    Colemanites have considerable heat sensitivity, so any setting in metal jewelry should be done very carefully. If worn as jewelry, they require protective settings. These gems are also slightly soluble in water. Don't soak these gems during cleaning and make sure they're dry before storing. Clean them only with a soft brush, mild detergent, and warm water. For more care recommendations, consult our gemstone jewelry cleaning guide.

    colemanite rough and cut set - California
    This rough and cut set features a cluster of tabular colemanite crystals and a faceted, 2.47-ct, 8 mm colemanite. Boron, Kramer District, Kern Co., California, USA. © Rob Lavinsky, www.iRocks.com. Used with permission.

    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.


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