0 a precious stone whose colour changes when the position of the person looking at it changes -- 蛋白石，猫眼石
By contrast, the accumulation of opal is strongly influenced by dissolution in the water column.
The light sheet travels parallel to the cylinder axis, strikes a 3-10 cm length of the meniscus, and is reflected onto a plate of opal glass.
Opal is my friend, but she really isn't my friend.
Opal alerts us to another attitude.
Small quantities of amethyst, peridot, and black opal are also produced.
Contrarily, "opalescence" is correctly applied to the milky, turbid appearance of common or "potch" opal.
Wealthy women wore jewels such as emeralds, aquamarine, opal, and pearls as earrings, necklaces, rings and sometimes sewn onto their shoes and clothing.
Gems were also mined, including opal and emerald.
