White Metal is any alloy that is light-colored, and is used especially as a base for plated silverware, ornaments and jewelry. Some of the metals used to create this alloy are antimony, tin, lead, cadmium, bismuth and zinc. Not all of these metals are found in all white metal alloys, but are combined to achieve a desired need, such as being able to be casted and polished.
Opal is a hydrated amorphous form of silica. It is deposited at a relatively low temperature and may occur in the fissures of almost any kind of rock, being most commonly found with limonite, sandstone, rhyolite, marl, and basalt. Precious opal ranges from clear through white, gray, red, orange, yellow, green, blue, magenta, rose, pink, slate, olive, brown, and black. Of these hues, the black opals are the rarest, whereas white and greens are the most common.