Scorodite Value, Price, and Jewelry Information

faceted scorodite - Namibia
Scorodite: Tsumeb, Namibia (1.0). Photo © Joel E. Arem, PhD, FGA. Used with permission.

With lovely colors and intense pleochroism, faceted scorodite is a prize for collectors of the rare and unusual. However, it’s too soft for jewelry use.

Scorodite Value

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

Scorodite Information

DataValue
NameScorodite
Is a Variety ofVariscite
Crystallography Orthorhombic. Crystals pyramidal, tabular, prismatic; massive, crusts.
Refractive Index Varies by locality, 1.738-1.816. See "Identifying Characteristics" below.
Colors Pale grayish green, yellowish brown to brown, colorless, blueish green, blue, violet.
Luster Vitreous to resinous.
Fracture Subconchoidal
Hardness 3.5-4
Specific Gravity 3.28-3.29.
Birefringence Varies by locality, 0.027-0.031. See "Identifying Characteristics" below.
Cleavage Imperfect
Dispersion Relatively strong.
Luminescence None.
Transparency Translucent to Semi-Transparent.
Absorption Spectrum One line at 4500, broad absorption in the green (Tsumeb).
Phenomena Color change (very rare).
FormulaFe3+AsO4 · 2H2O
Pleochroism Intense: purplish/bluish (Tsumeb).
Optics Biaxial (+), variable 2V. See "Identifying Characteristics" below.
EtymologyFrom the Greek skorodon for “garlic,” because the material emits the typical garlic odor of arsenic when heated.
OccurrenceA secondary mineral resulting from the oxidation of arsenious ores.
scorodite - Portugal
“Scorodite-170221,” Alto das Quelhas do Gestoso Mines, Gestoso, Manhouce, São Pedro do Sul, Viseu District, Portugal. Picture width 1.5 mm. Collection and photograph Christian Rewitzer. Licensed under CC By-SA 3.0.

Comments

Scorodite belongs to the variscite mineral group. It forms series as the ferric iron analogue (Fe3+) with mansfieldite (AlAsO4 · 2H2O), yanomamite (InAsO4 · 2H2O), and strengite (FePO4 · 2H2O).

Although not a rare mineral, faceted scorodites are extremely rare. A low Mohs hardness score of 3.5 to 4 and imperfect cleavage make them very susceptible to scratches and blows. Thus, faceted pieces would make interesting collector’s gems rather than practical jewelry stones.

scorodite - Cornwall, UK
“Scorodite,” Wheal Gorland, St, Day, Cornwall, UK. Photo by the University of Exeter. From the collection of the Royal Cornwall Museum, Truro, Cornwall. Licensed under CC By 2.0.

Identifying Characteristics

Rare specimens display color change, from blue-green in daylight to blueish purple or grayish blue in incandescent light.

Scorodites may have a greenish-white streak. Please note that streak testing may harm or destroy your specimen. Conduct it on a piece of rough, never a finished gem, only as a last resort.

Optical Properties of Scorodite from Various Localities

α

β

γ

Birefringence

2V

Durango, Mexico

1.784

1.795

1.814

0.030

75°

Idaho

1.738

1.742

1.765

0.027

60°

Oregon

1.741

1.744

1.768

0.027

40°

Tsumeb, Namibia

1.785

1.796

1.816

0.031

75°

faceted mansfieldite - scorodite series
Mansfieldite, yanomamite, and strengite occur far more rarely than their fellow series member scorodite. Accordingly, faceted examples of these minerals, like this pear-cut mansfieldite, are even rarer than scorodites. 2.99 cts, 12.6 x 7.8 mm, Algeria. © Rob Lavinsky, www.iRocks.com. Used with permission. (Images combined to show details).

Synthetics

Scientists have synthesized scorodite, including crystals, for research into the safe disposal of arsenic. However, there is no known jewelry use of this material.

Consumers may encounter so-called “scorolites” for sale online. Often marketed as “scorolite opals,” they are, in fact, simulants, usually purplish glass or quartz pieces. Occasionally, you might encounter this same material offered as scorodite. Keep in mind that “scorolite” is not a synonym or alternate name for scorodite. Quartz and glass are distinct gemologically from scorodites. (This confusion may stem from a typo in a paper on geo-environmental hazards in groundwater in India).

Enhancements

None known.

scorodite - China
“Scorodite,” 2.0 x 1.6 x 0.9 cm, Hezhou, Guangxi Zhuang Autonomous Region, China. © Rob Lavinsky, www.iRocks.com. Used with permission.

Sources

Tsumeb, Namibia produces beautiful, pleochroic blue/purplish crystals, some gemmy, up to 25 mm long.

Durango, Mexico and Ouro Preto, Minas Gerais, Brazil also yield fine, blue crystals, some gemmy.

Other notable crystal sources include

  • United States: California; Idaho; Nevada; Oregon; South Dakota; Utah; Washington; Wyoming.
  • Algeria; Ontario, Canada; China; Japan; Portugal; United Kingdom.
stalactitic scorodite - Algeria
An unusual stalactitic growth of scorodite. 7.7 x 6.2 x 1.0 cm, Djebel Debar, Hamman, Meskhootine, Constantine Province, Algeria. © Rob Lavinsky, www.iRocks.com. Used with permission.

Stone Sizes

Scorodites almost always make small faceted gems. As a reasonable maximum, expect about five carats. However, even that would be very large for the species.

  • Smithsonian Institution (Washington, DC): 2.6 (purplish, Namibia).

Care

Scorodites just don’t have the wearability to serve as jewelry stones. Furthermore, they’re soluble in acids and contain arsenic. While this shouldn’t pose a problem for wear or display, gem cutters should take precautions to prevent inhaling particles, protect their eyes, and wash their hands while working with scorodites.

scorodite gems - Namibia
Scorodite: Tsumeb, Namibia (1.15, 1.50). Photo © Joel E. Arem, PhD, FGA. Used with permission.