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.
Rose Gold gets its rosy tint by mixing copper with gold. The ratio of gold to copper is usually 3:1, but varying percentages can be used as well, the intensity of the color differs according to the ratio of gold and copper. Jewelry with rose gold plating gives off a quality of elegance and femininity.