Chrysoprase is one of the rarest gemstone varieties of chalcedony quartz. Chrysoprase is available in many shades of green, ranging from light, mint-green to deep apple-green. Most green gemstones are colored by chromium or iron, but this rare form of cryptocrystalline quartz is colored by nickel impurities. Until the introduction of another rare green-blue chalcedony known as 'gem silica' or 'chrysocolla chalcedony', chrysoprase was considered the most valuable of all quartz gemstones beads. Some of the finest specimens are said to come from Central Queensland, Australia. Fine Australian chrysoprase can possess a translucency, luster and vivid green color reminiscent of fine quality jade.
Wednesday, May 27, 2015
Friday, May 22, 2015
Amazonite is known as the 'Amazon stone' and was named after South America's Amazon River, which flows through the heart of Brazil. It is a green semi precious gemstone variety of microcline, one of the semi precious gemstone varieties of feldspar. Amazonite is famed for its striking jade-like color and luster. Most amazonite semi precious gemstones are mottled, with uneven color distribution. Its green to light bluish-green color is owed to traces of iron. Fine top-quality amazonite can easily be mistaken for precious jade. As a variety of feldspar, amazonite semi precious gemstone beads is reasonably hard and is considered durable enough for most jewelry applications. Amazonite looks best when set into silver or white gold jewelry mountings. Amazonite semi precious gemstone with a high saturation of color, interesting patterns and evenly distributed color are considered the most desirable. Amazonite jewelry is extremely popular in South American countries.
Wednesday, May 20, 2015
Carnelian is a brownish-red to red-orange variety of chalcedony. The distinctive red-orange color of carnelian is a result of trace amounts of iron. Sometimes the name 'sard' is used to refer to the darker colors of carnelian, though there is no clear distinction between carnelian and sard.
Carnelian is one of the oldest known gemstones. It was widely used in ancient Rome to make insignia and seals for imprinting on letters or important documents because hot wax does not stick to carnelian. It also is one of the birthstones listed in the ancient Arabic, Hebrew and Roman tables, and is a birthstone for the zodiacal sign of Virgo.
Today, carnelian is used for cabochons and precious gemstones beads. It is also carved to produce cameos, intaglios and other sculptures. The most important carnelian deposits are found in Brazil, Uruguay, India and Madagascar.
Many carnelian gemstones beads being offered for sale on the market today are actually agate precious gemstones beads that have been dyed and then heat-treated. But there is a way to identify natural carnelian. The dyed agate will display striping when held against the light, while the natural carnelian will show a cloudy distribution of color. Natural carnelian is becoming increasingly rare.
Carnelian was used as a talisman by people dating back as early as the ancient Babylonians and Greeks. Many Muslims believe that carnelian brings peace and happiness to its owner. This belief is attributed to the fact that Mohammed wore a ring set with a carnelian seal. Emperor Napoleon jealously guarded a carnelian seal that he found in an Egyptian campaign and often wore as a watch charm.
Tuesday, May 19, 2015
The garnets are differently colored minerals all with a common crystal structure and varying (but related) chemical compositions, with members ranging from the common red almandite to the rare green tsavorite and demantoid. Six common varieties of garnet are recognized based on their chemical composition. They are pyrope, almandine, spessartite, grossularite, uvarovite and andradite.
Grossularite garnet is a calcium-aluminum garnet. The name grossularite is derived from the botanical name for the gooseberry, grossularia. The grossularite group includes the light to medium green grossularite; the cinnamon-colored hessonite; the colorless leuco garnet; a dense opaque green garnet called hydrogrossular; and the rare and valuable deep green tsavorite garnet, colored by chromium. Grossularite garnet ranges in color from lemon yellow to greenish-yellow, yellowish-green and even mint green.
Grossularite varies in hardness from 6.5 to 7.5 on the Mohs hardness scale. The best specimens of grossularite can easily be confused with the more expensive demantoid garnet. Garnet's good hardness combined with its absence of cleavage makes it a very durable natural gemstone beads for all kinds of jewelry.
Deposits of grossularite are found in a number of locations, including Canada (Quebec), the USA (Vermont), Africa (South Africa, Tanzania, Kenya and Mali), Russia, Pakistan and Sri Lanka.