Malachite was used as jewelry thousands of years ago by the ancients Egyptians. Malachite is usually cabochon set in silver . Malachite has a hardness of 4 and a specific gravity of 3.80. Malachite is sometimes coated with colorless wax, oil, or hardening agents to increase its durability and enhance its appearance. A malleable substance is easily hammered into thin sheets.
Gold is the most malleable metal.
Maltese cross is a cross whose four equal-length arms get larger the farther they get from the center. It is actually iron pyrite . Marcasite is generally faceted . The Czech guilloche pin above is studded with marcasites. They were bought by Trifari in 1982.