Realgar Value, Price, and Jewelry Information


realgar - wheel of light pendant
“Wheel of Light” (patent pending). Pendant made from rock quartz, realgar, 24k gold, and diamond. Concept, design, and production by Nature's Geometry. Gold design collaboration with Paula Brent. © Brian Cook. Used with permission.

Although this common arsenic sulfide mineral occurs worldwide, cut gem-quality realgar is extremely rare. This fine, red stone is very fragile, difficult to cut, and nearly impossible to wear.

Realgar Value

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

Realgar Information

DataValue
NameRealgar
Crystallography Monoclinic. Crystals prismatic, striated; compact, powdery.
Colors Dark red, orange-red.
Luster Resinous to greasy.
Fracture Conchoidal. Sectile.
Hardness 1.5-2.
Specific Gravity 3.56.
Birefringence 0.166.
Cleavage Good 1 direction.
Dispersion Strong.
Luminescence None.
Spectral Not diagnostic.
Transparency Translucent to transparent.
FormulaAsS.
Pleochroism Strong: colorless to pale yellow.
Optics a = 2.538; β = 2.684; γ = 2.704. Biaxial (-), 2V: 40°.
EtymologyFrom the Arabic rahj-al-ghar, meaning “powder of the mine.”
OccurrenceLow-temperature hydrothermal vein deposits, especially with ores of lead and silver.
realgar - China
“Realgar,” Jiepaiyu Mine (Shimen Mine), Shimen As-(Au) deposit, Shimen Co., Changde Prefecture, Hunan Province, China. © Rob Lavinsky, www.iRocks.com. Used with permission.

Comments

With rich red to orange-red colors, realgar has a hardness of only 1.5 to 2. A penny could scratch it. Since it’s sectile (cuttable) with good cleavage, faceting presents challenges. Stones seldom occur with transparency. Furthermore, this mineral decomposes slowly in light and turns into yellow, even softer, pararealgar. To cap all this, realgar also contains arsenic. “Ruby arsenic” and “ruby sulfur,” older names for this mineral, allude to its color and noxious components. (Of course, rubies and realgars are distinct gem species).

Not surprisingly, although realgars make lovely gems, you’ll find very few of these cut. Those will most likely reside in gem collections.

This mineral is one of the principal sources of arsenic. It has a long history of use as a poison as well as a medicine in traditional Chinese and Indian Ayurvedic practices. From ancient times to the Renaissance, cultures from the Mediterranean region to China used realgar to produce red pigment. Tanners used it as a hair remover.

realgar and pararealgar - Nevada
Red realgar exposed to light has started transforming into yellowish-orangish pararealgar. “Realgar & Pararealgar & Calcite on Marble 2,” Getchell Mine, northern Osgood Mountains, northern Nevada, USA, by James St. John. Licensed under CC By 2.0.

Identifying Characteristics

Realgars have an orange to red streak. Keep in mind that streak testing can destroy your specimen. Conduct it on a piece of rough, never a finished gem, only as a last resort.

Red cinnabar gems can come close to realgars in appearance, hardness (2 to 2.5), and streak. However, they have a far greater specific gravity, higher birefringence, and different optic character. Their toxicity also differs. Cinnabar contains mercury, not arsenic.

Synthetics

Artisans have synthesized realgar for centuries to make red pigments by heating orpiment, another arsenic sulfide. Gem use of this material is unknown and most unlikely.

Sources

Gem-quality sources for realgars include:

  • United States: Boron, California; Getchell Mine and Manhattan, Nevada; Mercur, Utah; King County, Washington (fine crystals up to 2 inches long, some gemmy).
  • China; Czech Republic; Germany; Japan; Peru; Romania; Slovakia; Switzerland.
realgar - faceted
Realgar: Washington (0.65). Photo © Joel E. Arem, PhD, FGA. Used with permission.

Stone Sizes

Occasional fragments of Washington crystals will cut gems to about 3 carats.

Care

A jeweler’s torch could easily reach the temperature at which realgar melts, 307° C (585° F). Use great caution when working with this gem. Always clean yourself properly and avoid inhaling dust or fumes when handling this mineral. For more safety recommendations, consult these guidelines.

Store any realgars in a dark container to avoid decomposition. Avoid storing them with other harder, more common gemstones to avoid scratches. Don’t put realgars in contact with water or steam. This can also cause a release of toxic fumes.

realgar - Romania
“Realgar,” Cavnic, Maramures Co., Romania. © Rob Lavinsky, www.iRocks.com. Used with permission.