The pin above is by Trifari . Pink topaz is usually created by irradiating common yellow topaz. Topaz has a hardness of 8 and a specific gravity of 3.5-3.6. A plane of symmetry is a plane that divides a solid into two mirror-image pieces of the solid. The thickness of the metal coat varies.
Platinum is related to iridium .
Iridium and platinum are frequently alloyed together, since the Irridium increases the workability of the platinum. Platinum was only discovered in the 1700's in Russia. Platinum is abbreviated Pt. and Plat. Cells of enamel are surrounded by delicate wire. A point is a hundredth of a carat or 0.002 gram.