Photo of Platinum in Processed & Rough Form
Platinum is a mineral with a hardness of 4 out of 10 on the Mohs scale of mineral hardness [?]. These Cubicly structured gems are made of nothing more than Platinum, their full chemical compound being Pt.
Platinum is a rare and precious metal that occurs as a Native Element, one of the rarest in the Earth's crust.
It resembles silver, but it is less reactive and does not tarnish in air, and is thus considered a noble metal. Its greater hardness, higher density, and high melting point also distinguish it from silver.
Like gold, another noble metal, the only common acid combination to dissolve it is aqua regia, a mixture of concentrated hydrochloric and nitric acids.
Platinum appears rarely in small, poorly formed crystals, or in grains, plates, or even more rarely, as nuggets. It is silver gray in color.
It is medium hard, extremely heavy, ductile, malleable and has no cleavage. It is slightly magnetic when small impurities of iron are present.
Its primary origin is in the early segregation phase of mafic and ultramafic rocks (dunite and serpentinite).
Because of its very high specific gravity, it is mainly concentrated in river and marine placers, recent or fossil. It is plentiful in rivers running down from the Urals (the famous Perm deposit in Russia). Primary deposits are at Sudbury (Canada), in the Bushveld complex (South Africa), the USA, Brazil, Colombia, and Peru. In several instances, diamonds were found when gold and platinum were being sought.
The specific gravity [?] for Platinum is 21.4, its refractive index [?] is None, and its double refraction [?] is None.
History
Platinum derives its name from the Spanish "platina," a diminutive form of "plata" meaning "silver."
The metal was used by pre-Columbian Americans near Ecuador to produce objects made of a white gold-platinum alloy. Italian writer Julius Caesar Scaliger described it in the 1500s as an unknown noble metal found between Darien and Mexico, "which no fire has yet been able to liquefy."
Industrial Usages
Platinum is more costly than gold, at times valued twice as much, but varies depending on industrial demand. Platinum coins, bars, and ingots are prized by traders and collectors, and surface scratches known as "patina" are considered a desirable feature.
It is used by fine jewellery makers. Platinum is the best metal for diamond mounting as it is not only white but much harder than gold. It is used by top-quality watchmakers as it neither tarnishes nor wears out.
It is a good conductor of heat and electricity. Its hardness, density, and melting point, together with its malleability and thermal stability make it useful for laboratory tongs crucibles, and electrical contacts in thermo couples.
It is also an exceptionally good catalyst, used in the chemical and petroleum industries.
Commercial platinum and its metals are obtained as a by-product from nickel and copper mining and processing.
Native platinum contains lesser amounts of other related native elements, namely iridium, osmium, palladium and rhodium. The refining of platinum is the principal source of these other "heavy metals." Impurities in platinum found in placer deposits or alluvial areas are easily removed by floating in liquid. Other impurities can be melted away due to their low melting point. As platinum is nonmagnetic, other magnetic minerals may be removed by an electromagnet.
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