#5 Iridium (Ir)
Iridium is probably the most unique members of the platinum family. Besides being the densest one of them all, it’s also the hardest one. In other words, it’s exceptionally good, even by the platinum group standards, at withstanding corrosion.
What’s more interesting, however, is that it isn’t exactly as expensive as the other group members, despite being better than most of them on most fronts. Maybe the reason is that it’s used in way too many common day-to-day items such as pens, compasses, watches, as well as medicines, automobiles, electronics, and the list goes on.
It’s also probably worth mentioning that iridium is actually a by-product of nickel, and made by processing platinum ores. Its largest producer is South Africa though it can be found in smaller quantities in several other countries as well.
#6 Osmium (Os)
Don’t go by the pretty looks of this metal. Osmium, a silvery and bluish looking metal, is probably one of the densest metals ever found on earth. Besides having a tremendously high melting point, it’s extremely hard and brittle, a rather rare quality to be found in a precious metal.
It’s rather unique set of qualities finds itself being used in industries such as the electrical one, for hardening platinum alloys, which are required to complete electrical contacts and filaments.