Onyx and Sardonyx Beads
Tiger's Eye Beads
Strands of Okapi Agate Gemstone Beads
Agate is silicon dioxide, a gemstone variety of the tectosilicate mineral quartz in the trigonal crystal system. Agate is a variety of chalcedony, quartz with an microcrystalline texture so fine that its crystalline nature is too small to see clearly even under strong magnification. Agate occurs in numerous varieties including banded, brecciated, dendritic, spotted and sagenitic forms and in endless color combinations. Although it also occurs in other rock types, agate is classically associated with cavities in basalts that cool so rapidly upon flooding the surface gas bubbles are trapped within. Silica dissolved from the lava coagulates as a gel inside the bubbles, eventually hardening and crystallizing into an agate nodule. As the lava weathers and decomposes, the more resistant agate nodules are freed and become buried in soil or may be transported through erosion and deposited in streams and along shorelines.
Agates are world-wide in occurrence with notable localities including Australia, Austria, Botswana, Brazil, China, Germany, India, Madagascar, Mexico, Russia, Uruguay, and the United States. Within the United States, California, Idaho, Michigan, Montana, North and South Dakota, Oregon, Texas, Washington and Wyoming are among the states with well known agate localities. The use of agate and other chalcedonies as ornamental stones is prehistoric. Agate is one of the 12 stones mentioned in the Bible description of the priest Aaron's chest plate. Onyx, a variety of agate with alternating black and white bands, was prized by ancient Romans who employed it in the fine art of cameo making. The German town of Idar-Oberstein has been famous for high quality agate work since the Middle Ages, and became especially famous for its carved agate bowls and other vessels.
Agate is most commonly presented in jewelry as cabochons, beads and carvings. Agate is a relatively tough and hard material (7 Mhos hardness) with good wear characteristics and resistance to abrasion. Agate wears well in rings and bracelets and is commonly employed as a gemstone in all types of jewelry. Agate does not have specific care requirements, but conservative gemstone precautions should be observed when cleaning and storing agate for the sake of preserving the original condition of the stone. It is safest to clean agates using warm water, mild soap and a cloth or soft brush. Do not use an ultrasonic or steam cleaner and keep agates out of contact with excessive heat, acids, ammonia and other chemical or abrasive cleaners.
|BeadStrand79 - 'Okapi' Agate Gemstone Beads 13mm Tube - $8.85
|Limited Stock: 1 Strand Available
Approximate Size: 13mm long x 4mm diameter.
Please note the image at left may be larger than life to help show the fine details.
Strand lengths are approximately 16 inches long and each strand contains approximately 30 beads.
Average strand weight approximately 12 grams.
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