Name       : Iridium
Symbol     : Ir
Atomic #   : 77
Atom weight: 192.2
Melting P. : 2410
Boiling P. : 4130
Oxidation  : +3, +4
Pronounced : i-RID-i-em
From       : Latin iris, "rainbow"
Identified : Smithson Tennant in 1803
Appearance : White, brittle metal
Note       : Most corrosion-resistant of all known metals
             
[Properties]

  Iridium is one of the heaviest of the Group-VIII metals. Being in Group-
VIII puts it in the company of blue-chip commercial metals such as
manganese, iron, cobalt, nickel, lead, and platinum.
  When iridium is cast from its molten state, it cools to a crystalline
from that makes it rather ductile. In this state, it can be drawn into
wire or pressed into sheets. Whereas most other metals, notably steel,
becomes less brittle after annealing (heating and slowly cooling), iridium
becomes brittle and completely unworkable.
  Iridium is known as a platinum metal because it is found in natural 
deposits of platinum. Iridium's twin element, osmium (Os, element 76), is
found there, too; so osmium, iridium, and platinum are found together,
both in nature and on the periodic table of elements.