Scorodite
Current inventory:  0 gems
 

  
Scorodite is named from the Greek word skorodon, for garlic, in allusion to its arsenic odor when heated.

Discovered in 1817;   IMA status: Valid (pre-IMA; Grandfathered)

Chemistry

Chemical Formula:

Fe³⁺AsO₄•2H₂O

Hydrated Iron Arsenate

Molecular Weight:

230.80. gm

Composition:

Iron

24.20 %

Fe

34.60 %

Fe₂O₃

Arsenic

32.46 %

As

49.79 %

As₂O₅

Hydrogen

1.75 %

H

15.61 %

H₂O

Oxygen

41.59 %

O

100.00 %

100.00 %

= TOTAL OXIDE

Classification

Mineral Classification:

Phosphates

Strunz 8th Ed. ID:

7/C.09-80

Nickel-Strunz 10th Ed. ID:

8.CD.10

8 : PHOSPHATES, ARSENATES, VANADATES
C : Phosphates without additional anions, with H₂O
D : With only medium-sized cations, RO₄:H₂O = 1:2

Related to:

Variscite Group, Scorodite-Yanomamite Series, Scorodite-Mansfieldite Series, Scorodite-Strengite Series.

Varieties:

Aluminian Scorodite, Phosphoscorodite

Synonyms:

Arsenic Sinter, Cupreous Arsenate of Iron, Cupromartial Arsenate, Loaisite, Martial Arsenate of Copper

Crystal Data

Crystallography:

Orthorhombic - Dipyramidal

Crystal Habit:

Crystals pyramidal {111}, tabular [001], or prismatic [010], with large {111}, {101}, {201}, {001}, many other modifying forms, to 5 cm. Commonly as crystalline crusts; may be porous, sinterlike, earthy, massive.

Twinning:

None

Physical Properties

Cleavage:

{201} Imperfect, {100} Poor, {001} Poor

Fracture:

Sub-Conchoidal, Splintery

Tenacity:

Brittle

Moh's Hardness:

3.5 - 4.0

Density:

3.27 (g/cm³)

Luminescence:

None

Radioactivity:

Not Radioactive

Other:

Soluble in acids; decomposed in strong alkalies. Alters to limonite.

Optical Properties

Color:

Pale leek-green, grayish green, liver-brown, pale blue, violet, yellow, pale grayish, colorless; may be blue-green in daylight but bluish purple to grayish blue in incandescent light; in transmitted light, colorless to pale shades of green or brown.

Transparency:

Translucent to Semi-Transparent

Luster:

Vitreous to Subadamantine, Subresinous

Refractive Index:

1.741 - 1.820  Biaxial ( + )

Birefringence:

0.027 - 0.036

Dispersion:

Relatively Strong; r > v

Pleochroism:

Weak, typically faint; blue-violet to blue-green

Occurances

Geological Setting:

A secondary mineral formed by oxidation of As-bearing sulfides.

Common Associations:

Pharmacosiderite, Beudantite, Carminite, Dussertite, Arseniosiderite, Adamite, Austinite, Vivianite, iron oxides

Common Impurities:

Al

Type Locality:

Stamm Asser Mine, Graul, Langenberg, Schwarzenberg District, Erzgebirge, Saxony, Germany

Year Discovered:

1817

View mineral photos:

Scorodite Mineral Photos and Locations

More Information

Mindat.org
Webmineral.com

Scorodite is not a rare mineral, but is very rare as a faceted gem. Gems are very small since gem quality crystals are typically very small. Scorodite gems may also rarely display a color change from green to violet under different types of light.

There are numerous occurrences of Scorodite, typically in small amounts. Some localities for well-crystallized material are: in Germany, from Schwarzenberg, Saxony, and in the Clara mine, near Oberwolfach, Black Forest. At Horní Slavkov (Schlaggenwald), Czech Republic. From Lölling, Carinthia, Austria. Found at a number of places in Gwennap, Calstock, and elsewhere in Cornwall, England. Occurs at Djebel Debar, Qacentina (Constantine), Algeria. Very large crystals from Tsumeb, Namibia. Large crystals from Antonio Pereira, Minas Gerais, Brazil. In Mexico, large crystals from the El Cobre mine, Aranzazú, Concepcíon del Oro, Zacatecas, and in the Ojuela mine, Mapimí, Durango. In the USA, in Utah, an ore mineral at Gold Hill, Tooele County, and in the Tintic district, Juab County; and from the Majuba Hill mine, Antelope district, Pershing County, Nevada. At the Kiura mine, Oita Prefecture, Japan, large crystals. From Broken Hill, New South Wales, Australia.
 

  
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