Danburite Value, Price, and Jewelry Information

Yellow cushion-cut danburite, 6.53 cts, 12.0 x 9.7 x 8.6 mm, Myanmar. © ARK Rare Gems. Used with permission.

Danburite

A very durable gemstone, danburite is an excellent choice for jewelry use. Although the mineral isn’t rare, large facetable pieces are scarce. Still, sufficient material exists for gem enthusiasts and adventurous jewelry lovers to add this lovely and underappreciated stone to their collections.

Danburite Value

Tried and true gem value factors apply to danburite. All other things being equal, larger, cleaner, better cut and better colored stones have a higher value per carat. However, a truly colorless specimen would surpass a very pale yellow or slightly pink stone in value per carat.

Princess-cut colorless 8.65-ct danburite, 12.26 mm, Russia. © Kosnar Gem Co. Used with permission.

The International Gem Society (IGS) has a list of businesses offering gemstone appraisal services.

Danburite Value via Gem Price Guide

Faceted 1 carat plus
Pink to /ct
Colorless to /ct
Other Colors to /ct
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Danburite Information

Data Value
Name Danburite
Colors Colorless, white, pink, light to dark yellow, yellowish brown, brown, blue.
Crystallography Orthorhombic; Crystals prismatic with wedge-shaped terminations, like topaz.
Refractive Index 1.627 - 1.641
Luster Vitreous to greasy.
Hardness 7
Wearability Excellent
Fracture Subconchoidal to uneven
Specific Gravity 2.97-3.03, usually 3.00.
Birefringence 0.008-0.009
Cleavage Indistinct
Dispersion 0.017
Luminescence Sky blue to bright blue-green in LW. Also, thermoluminescent (red).
Luminescence Present Yes
Luminescence Type Fluorescent, Phosphorescent, UV-Long
Transparency Transparent.
Absorption Spectrum Sometimes shows rare earth spectrum, so-called didymium lines.
Phenomena Chatoyancy (rare).
Formula

CaB2Si2O8
Pleochroism

Weak: pale-yellow/yellow.
Optics

a = 1.627-1.633; β = 1.633-1.637; γ = 1.636-1.641. Biaxial (-); 2V= 88° in red to green light; optically (+) at lower wavelengths.
Etymology

After the type locality, Danbury, Connecticut.
Occurrence

In dolomites; in carbonate veins in granitic rocks.
Inclusions

Fingerprints (healed fractures), hollow growth tubes.
danburite gem and crystal - Mexico

Danburite: Charcas, Mexico (8.5, crystal ~ 2 1⁄2 inches long). Photo © Joel E. Arem, PhD, FGA. Used with permission.

Comments

Danburite’s colors typically range from colorless to light yellow, pale pink, or tan. With poor cleavage and a hardness of 7, it ranks with popular jewelry stones such as quartz and topaz in toughness. Although its modest dispersion means cut danburites lack fire, properly cut gems are very bright. Rare specimens may also display chatoyancy.

cat's eye danburite - Bolivia

This danburite shows an unusual color, dark blue, as well as a rare chatoyant “cat’s eye” effect. Round cabochon, 0.73 cts, 5.1 mm, Alto Chapare District, Cochabamba Dept., Bolivia. © The Gem Trader. Used with permission.

Identifying Characteristics

Interestingly, most specimens fluoresce a sky blue color in longwave ultraviolet light and phosphoresce red when heated.

Synthetics

Laboratories have synthesized danburite for research into phosphorescence. However, there’s no known jewelry use for this material.

Enhancements

No known gem treatments.

danburite - type locality

Danburite mass with crude crystal faces, Danbury, Fairfield Co., Connecticut, USA. © Rob Lavinsky, www.iRocks.com. Used with permission.

Sources

First discovered in Danbury, Connecticut, gem-quality danburite has since been found in many locations. Other notable sources include the following:

  • Japan: Obira, Bungo, Kyushu, colorless crystals, sometimes gemmy.
  • Madagascar: yellow crystals at Mt. Bity, often gemmy.
  • Mexico: Charcas, San Luis Potosí, colorless, yellow, light pink (gemmy).
  • Myanmar: Mogok, yellow and colorless, sometimes large crystals (rolled pebbles).
  • Russia: colorless, gemmy material.
  • Bolivia; China; Tanzania; Vietnam.
Barion emerald-cut danburite - Madagascar

Golden yellow danburite, 32.97 cts, 20.93 x 16.25 mm, 32.97 cts, custom Barion emerald cut, Madagascar. © Kosnar Gem Co. Used with permission.

Stones Sizes

Danburites, especially colorless material from Mexico, typically range in size between 1 and 5 carats. Yellow gems from Myanmar between 7 and 10 carats are very rare.

  • British Museum of Natural History (London): Myanmar, wine-yellow, step-cut, flawless, 135.61.
  • Smithsonian Institution (Washington, D.C): 18.4 (Myanmar, yellow) 12.4; 10.5 (Mexico, colorless); 7.9 (Japan, colorless).
  • Los Angeles County Museum (Los Angeles): Madagascar, brownish, emerald cut, 115.
  • Royal Ontario Museum (Toronto, Canada): Russia, colorless, step-cut, 12.72.
  • Private Collections: 20 (Myanmar, peach color); 22.76 (Madagascar, yellow); 37 (Russia).
danburite - tanzania

Danburite, Merelani Hills, Arusha Region, Tanzania. © Rob Lavinsky, www.iRocks.com. Used with permission.

Care

Due to some heat sensitivity, avoid steam cleaning this gem. Otherwise, danburite requires no special care. You can use these gems for all jewelry applications, including rings and bracelets. Consult our gemstone jewelry cleaning guide for more care recommendations.

danburite - cut

Cut Danburite, Locality: Anjanabonoina, Ikaka, Ambohimanambola Commune, Betafo District, Vakinankaratra Region Antananarivo Province, Madagascar (0.47 cts). Photo by Didier Descouens. Licensed under CC By-SA 4.0.

by Joel E. Arem, Ph.D., FGA, Barbara Smigel, PhD. GG, International Gem Society