Discovered by W. Crookes at London, UK; isolated in 1862 by C. A. Lamy at Paris, France.
Remarks
Soft, silvery-gray metal. Tarnishes readily in moist air and with steam reacts to form TlOH. Attacked by acids, rapidly by
HNO3. Little used because of its toxicity, but still employed in special glasses.
Diagnostic tests:
Thallium and its salts are quite volatile when heated with the blowpipe
and impart an intense green color to the flame
test.
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 54 minerals with Tl in the Mineralogy Database.