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Opal Stone
Chemical Formula: SiO2nH2O
Mineral Name: Opal
Color: Opaque to translucent white with green, blue, yellow, orange, red crystals
Hardness: 5.5- 6.5
Specific Gravity: 1.98 - 2.20
About Opal Stone
Opal stones are actually an amorphous form of hydrous silica gel. They are the most challenging materials for making beads. Due to the accumulation of high percentage of water, opal may deteriorate in heat and cold. They are fragile and tend to chip and scratch easily. In addition to their beautiful and attractive appeal, opal stones are used as a lucky charm in some countries.
Opal has derived its name from the Sanskrit word “Upala†meaning a precious stone. The red color opal beads look very attractive. During the manufacturing of these beads, instead of concentrating at the particular red color, the manufacturers diversify their concentration in different color shades. As a result, opal beads are now available in various hues raging from translucent to opaque form. They are available in red, green, blue, yellow, orange and many more. Opal is a mineral of hydrated silica. Opal Stones are luminous and iridescent with inclusions of many colors. Opal is a mineral composed of noncrystalline (amorphous) silica (and some water) and is a species of quartz. It derives its name from the Sanskrit name for precious stone; upala.The various varieties of opals are: common opal, opalescent precious opal (white or black, with a rainbow-like iridescence caused by tiny crystals of cristobalite), and fire opal (a milky stone that is firey orange to red in color with no opalescence).
Occurrence of Opal Stone Beads
These beautiful opal beads are mainly Peru, USA, Nigeria, Brazil, Japan, Honduras, Kenya, Czechoslovakia, Canada, Australia and Mexico. The relative hardness of these beads is 6. Opal is mainly composed of noncrystalline (amorphous) silica (and some water) and is a species of quartz. Opals show a play-of-color when the spheres are uniformly arranged in regular 3-dimensional layers. The range of colors is determined by the size of the spheres. The brighter and more distinctive the play-of-color, the better the opal.
Varieties of Opal Stone Beads
Due to the high degree of versatility, there are numerous varieties of opal, each is attractive in its own way. The harlequin opal, as the name suggests, gives a rich play of prismatic colors flashing from minute fissures. It is translucent and spangled with many shades of red, blue and yellow specks. The other popular varieties are Peruvian Opal, Common Opal, Opalescent Precious Opal, Precious Opal, Australian Opal and Fire Opal.
Common Opal is dull white or milky blue. Fire opal is hyacinth-red to honey-yellow and shows intense orange and red fire-like reflections. Water opal is similar to fire opal, but is colorless. And Precious opal, if held to the light, shows a marvelous display of brilliant colors.
