Lapis is a deep blue semi-precious stone prized since antiquity for its intense color. The intense blue color is due to the presence of the trisulfur (S3) radical anion in the crystal. Lapis lazuli is a rock whose most important mineral component is lazurite. Most lapis lazuli also contains calcite (white), sodalite (blue), and pyrite (metallic yellow). Lapis takes an excellent polish and can be made into jewelry, carvings, boxes, mosaics, ornaments, small statues, and vases.
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.