Hard, lustrous, silvery metal of the platinum group. Stable
to air and water, inert to all acids, but fused NaOH will attack it. Used
in special alloys and spark plugs.
Diagnostic tests:
There are no simple chemical tests for iridium. The element is usually
found as an alloy or a sulfide mineral with other platinum group metals. Atomic Absorption
Spectroscopy is used for quantitative analysis and Energy Dispersive
Analysis of X-rays (EDAX) is used for qualitative analysis.
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 25 minerals with Ir in the Mineralogy Database.