This article has been reviewed and approved by the following Topic Editor: Sidney Draggan (other articles)
Background
The name platinum refers to a mineral, an element and a group of elements. As an element, platinum (chemical symbol Pt) is a silvery-gray metal with an atomic number of 78. It belongs to a group of elements that are in the second and third triads of Group VIII of the Periodic Table of the Elements.
The platinum group of elements consists of metals with similar physical properties. They are among the rarest elements in the Earth’s crust. They have high melting points, are dense or heavy (mineralogists say they have a high specific gravity), and are very non-reactive to other elements and ions. The platinum group elements include: ruthenium (44), rhodium (45), palladium (46), osmium (76), iridium (77) and platinum (78). Of these elements, only platinum and palladium are found in a pure form in nature. The others occur in nature as natural alloys with platinum and gold, for example. In industry people refer to this group of elements as the platinum group metals, or simply as PGM.
As a mineral, platinum occurs in dark silicate rocks with minerals containing iron and magnesium. It is usually found as fine grains or flakes scattered throughout the rock and rarely as large nuggets. It crystallizes in the cubic crystal system, but rarely forms actual crystals. Platinum is metallic and, like gold and silver, is malleable (it can be hammered into sheets) and ductile (it can be drawn into wire). Most naturally occurring platinum is actually a mixture of platinum and iridium.
...