The Mineral stibarsen
Stibarsen is a natural mixture of the elements arsenic and antimony, and its name is a combination of stibium (which is the latin name for antimony), and arsenic. Allemontite, another name for this mineral, is usually used to describe the ratio percentage of antimony to arsenic. Allemontite is named after Allemont, France, an important locality for this mineral.
Any mixture of arsenic and antimony that constitutes 80% or more of one element is classified as that element. For example, a specimen with a ratio of 80% arsenic and 20% antimony is recognized as Arsenic
. Conversely, a specimen with 80% antimony and 20% arsenic is recognized as Antimony
. Any combination with less than 80% of either arsenic or antimony is classified as Stibarsen.
Tin-white to gray
3 - 4
1,1 - basal. Cleavage is rarely seen since crystal faces are so uncommon.
|Other ID Marks
Tarnishes dark gray
Any mixture of arsenic and antimony, including Stibarsen.
(Allemontite is not scientifically recognized as a mineral species, but rather a descriptive name.)
Allemontite with a greater content of antimony than arsenic.
Allemontite that has an equal quantity of antimony and arsenic.
Allemontite with a greater content of arsenic than antimony.
Stibarsen has come from the Canada at the Engineer mine, Atlin, British Columbia; and at the Hemlo Gold deposit near Lake Superior in Ontario. In Europe, specimens have come from Allemont and Chelenches (Dauphine), France; and Pribram, Bohemia, Czech Republic. Lustrous botryoidal forms come from Mexico at Moctezuma, Sonora.
U.S. occurrences of Stibarsen are the Ophir Mine, in the Comstock Lode, Storey Co., Nevada; and at American Eagle, Gunnison Co., Colorado.
Common Mineral Associations
Quartz, Antimony, Arsenic, Siderite
Distingushing Similar Minerals
Antimony and Arsenic are indistinguishable from Allemontite / Stibarsen through common testing methods; the only way to distinguish them is through complex scientific tests.