Scorodite Value, Price, and Jewelry Information

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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 Information

Data	Value
Name	Scorodite
Is a Variety of	Variscite
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.
Hardness	3.5-4
Fracture	Subconchoidal
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.
Luminescence Present	No
Transparency	Translucent to Semi-Transparent.
Absorption Spectrum	One line at 4500, broad absorption in the green (Tsumeb).
Phenomena	Color change (very rare).
Formula	Fe³⁺AsO₄ · 2H₂O
Pleochroism	Intense: purplish/bluish (Tsumeb).
Optics	Biaxial (+), variable 2V. See "Identifying Characteristics" below.
Optic Sign	Biaxial +
Etymology	From the Greek skorodon for “garlic,” because the material emits the typical garlic odor of arsenic when heated.
Occurrence	A secondary mineral resulting from the oxidation of arsenious ores.

“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,” 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°

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,” 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.

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.