Probably first isolated by Alertus Magus (1193-1280).
Remarks
Metalloid with several allotropes, Grey alpha-arsenic is metallic, soft
and brittle, tarnishes, burns in O2, resists attack by water,
acids, and alkalis. Attacked by hot acids and molten NaOH. Uses: alloys,
semiconductors, pesticides, wood preservatives, and glasses.
Diagnostic tests:
Arsenides, sulpharsenites, etc. (As2-), give off fumes when
roasted on charcoal, usually easily recognized by their peculiar garlic
odor. In the open tube test, they give a white, volatile, crystalline
sublimate of As2O3. The blue flame
test for arsenic may be visible when the sublimate is blasted with the
blowpipe flame.
In the closed tube test with
sulfur, they yield a sublimate of dark brown-red when hot and red or
reddish yellow when cold; or a black to gray mirror sublimate of metallic
arsenic.
Arsenates (AsO4) can be detected by the garlic odor yielded
when a mixture of the powdered mineral with charcoal dust and Na2CO3
is heated with a reducing flame on charcoal.
References
Emsley, J., 1991; THE ELEMENTS : Sec. Ed.,
Clarendon Press, Oxford, 251 p.
(* - Mineral Name Is Not IMA Approved)
(! - New Dana classification added or changed from Danas New Mineralogy)
(? - IMA Discredited Mineral Species Name)
There are 565 minerals with As in the Mineralogy Database.