It is a rich yellow color, and is very soft. It is generally considered to be too soft for use in most jewelry Sterling silver is an alloy consisting of 925 parts pure silver, and 75 parts other metals such as copper and zinc. The addition of these metals makes the silver stronger and harder. Amethyst and citrine are both members of the quartz family along with smoky and rose quartz, agate, bloodstone and more. A diamond is by far the hardest of any gemstone.
Platinum is the hardest of the pure precious metals.
Much harder than PURE gold and silver. Although platinum is the hardest of the pure precious metals, certain gold alloys, especially 14 karat white gold, are much harder. Tourmaline occurs in pink, red, blue, green, brown, and many colors in-between. A cabochon is a smooth rounded stone with no facets. Almost any gemstone can be cut as a cabochon.