- CULTURED PEARLS
- SEMI PRECIOUS GEMS
- PRECIOUS GEMS
- GEMSTONE BEADS
- GEMS PYRAMIDS
Chrysoprase is a Semi precious stone as it comes under the category Chalcedony, which itself is a Semi precious stone. The finest chrysoprase is usually described as apple green. It is sometime called imperial chrysoprase, an obvious attempt at a comparison to jadeite. It is a vivid visually pure green between sixty-five and seventy percent tone. The material from Marlborough Creek normally ranges from a visually pure green to a slightly bluish green. Gems from Yerilla may show a yellowish secondary hue. This yellowish secondary hue is considered a fault. Gemstones with even the slightest trace of a visible yellow secondary hue are far less desirable.
Gray is the normal mask or saturation modifier in the Semi precious gem, chrysoprase. The best of the Australian material shows no gray at all and can be best described as a vivid apple green. The general run of chrysoprase from these two sources is remarkably consistent in hue, saturation, and tone.
Another variety called lemon chrysoprase is found in Western Australia. It is a pale opaque lime green color and is actually not a chalcedony at all but a nickeloan magnesite.Posted on Thursday, November 10, 2011 - 12:42
Chrysoprase (Semi precious stone) is a green chalcedony that owes its “apple green” color to the presence of trace amounts of pimelite, a type of nickel. Chrysoprase is very close-grained microcrystalline quartz.
Two sources of chrysoprase were discovered recently in Australia, each producing, in substantial quantities, most of the material available in the market today. The first and most important source was a vast deposit found in 1965 at Marlborough Creek, Queensland. The second was unearthed in Western Australia in the Yerilla District in 1992. Material from Marlborough Cheek shows the purest green hue and is the finer of the two. Other sources include Brazil, and Kazakhstan in Central Asia, a legendary find, much of which later was determined to be green opal. Opal of a similar color is often associated with chrysoprase. In earlier times it was referred to as chrysopal.
Writting Original articles by Navneet Gems and Minerals, the source of Gem Chrysoprase, Chalcedony and other Semi precious and Precious gemstones.Posted on Thursday, November 10, 2011 - 12:25
Malachite and drusy quartz are the usual inclusions found in gem chrysocolla. Though technically inclusions, either can add to the beauty of a cut gemstone.
Inclusions and value
Drusy, tiny colorless quartz crystals growing on the gem, are the most sought after inclusions in gem chrysocolla. Although perfection in all characteristics tends to be the way the finest gems are defined, the aficionado should be alert to pleasing compositions of gem chrysocolla juxtaposed with inclusions of drusy quartz. Malachite, since it is green, is a less desirable inclusion, though it can show a pleasing juxtaposition of color and pattern in a vivid blue gem. It is the skill and sensitivity of the cutter that makes all the difference is such cases.
The rarity factor
Gem chrysocolla with the qualities discussed above is extremely rare. I might find one fine piece every few years. If a fine piece is on offer, the aficionado must be prepared to accept the price, or not have a second opportunity for many years.
Writting Original articles by Navneet Gems and Minerals, the source of Gem Chrysocolla, Chalcedony and other Semi precious and Precious gemstones.Posted on Tuesday, November 8, 2011 - 11:33
Crystal in Gem Chrysocolla
Given the consistency of hue, saturation, and tone, it is the degree of transparency that defines the various grades of gem chrysocolla. This gem is never completely transparent; it is translucent. It is the degree of translucency that is the defining factor. The greater the translucency the more the gem will be seen to glow in the light. It can be said that crystal is really the first C of connoisseurship in gem chrysocolla, as well as in the other agate varieties to be discussed in this section. Visually pure blues with a high degree of translucency is more desirable than an opaque pure blue.
Gem chrysocolla is often cut in freeform (nonsymmetrical) shapes. Shape has little effect on value except that the more interesting freeforms may command a premium. Particularly translucent gems will some-times be faceted.
Writting Original articles by Navneet Gems and Minerals, the source of Wholesale Gem Chrysocolla, and other Chalcedony Gemstones, and Semiprecious and Precious Gemstones.Posted on Tuesday, November 8, 2011 - 11:22
It is estimated that over eighty percent of gem chrysocolla is subject to a degree of color fading when exposed to a dry environment. This is particularly true of the Mexican material. As the stone dries out, the translucency and the color saturation of the gem are both diminished. According to Chris Boyd, a dealer who spends summers in upstate New York and winters in Arizona, and who has worked with gem chrysocolla for many years, fading is an issue in areas with an average relative humidity below fifty-five percent. His stone looks much better in New York than in the Arizona desert. Fading can be reversed when the gem is rehydrated by directly exposing it to moisture or to a moist environment for a short period of time.
Writting Original articles by Navneet Gems and Minerals, the source of Wholesale Non-color fading and fading Chrysocolla, both.Posted on Monday, November 7, 2011 - 13:03
Vividness of hue is the quality that assures gem chrysocolla a place among the precious gemstone. The hue varies from a slightly greenish medium dark-toned (fifty to seventy percent) turquoise blue to a similarly toned visually pure sky blue. The green secondary hue rarely exceeds ten percent. As with all blue gems, the smaller the percentage of secondary green, the more desirable the gem. Gem chrysocolla rarely shows any evidence of either a gray or brown mask. Thus, it has a consistently vivid hue. The tonal range of gem chrysocolla is also remarkably consistent.
Writting Original articles by Navneet Gems and Minerals, the source of Semi-Precious and Precious Gemstones from Bangkok, including Wholesale Chrysocolla.Posted on Monday, November 7, 2011 - 12:24
The rare rich sky-blue variety of chalcedony has been referred to variously as silicated chrysocolla, gem silica, agated-chrysocolla, and gem chrysocolla. The issue lies with the term chrysocolla. True chrysocolla is a soft, noncrystalline mineral that owes its vivid color, ranging from turquoise to sky blue, to the staining effect of copper oxides. Gem chrysocolla, by contrast, is a relatively hard cryptocrystalline silicate that has been stained blue by the same copper oxides.
Given the vast difference in hardness, the aficionado should have little difficulty in separating the two materials by appearance alone. True chrysocolla is opaque, with subvitreous luster, and has a hardness of two to four on the mohs scale. Materials of this hardness normally can be scratched with a copper penny. Gem chrysocolla may be opaque to translucent and have a vitreous, or glassy, surface luster and, with a hardness of seven, it is harder than steel. Standard gemological tests can easily separate the two materials. True chrysocolla may have all the beauty of gem chrysocolla, except the luster, but it lacks the requisite hardness and durability necessary to qualify it as a gemstone.
Much of the finest gem chrysocolla is found in the copper mines of Pinel County, Arizona. In the 1960s a deposit of the gem was found on the island of Taiwan. In the East, gem chrysocolla is sometimes referred to as “blue jade,” an unfortunate term that further adds to the linguistic confusion.
Writting Original articles by Navneet Gems and Minerals, the source of Wholesale Gem Chrysocolla, and many more Chalcedony.Posted on Monday, November 7, 2011 - 12:15
Since at least 2000BC, Chalcedony has been subjected to heat treatment to create carnelian. Heat treated agates were among the treasures unearthed from the tomb of King Tutankhamen (1300BC). Most of the carnelian currently on the market has been heat treated. Agate is quite porous and can be soaked in acid to create a dark outer layer in preparation for carving en cameo. Porosity also makes chalcedony a good candidate for dyeing. Dyeing will sometimes produce a very highly saturated unnatural-looking hue. For example, “green onyx” is colorless chalcedony that has been dyed rich dark green; it looks simply too green to be true and it is! Black onyx is also universally dyed. The blue varieties of chalcedony are also subject to dyeing. Under magnification, natural color agate will usually show evidence of thin color bands. Specialists call these bands fortifications of color. Heat treatment will burn out the bands. Acid treatment produces a dark, dense, “burnt” look in carnelian (Chalcedony). Many first-to third century Roman intaglios, engraved seal stones, fit this description perfectly. Because agates are relatively reasonable in cost, treatment are almost never disclosed to the buyer.
This section will consider the five most beautiful and commercially important varieties of chalcedony: gem chrysocolla, Holley blue and Mojave blue agate, carnelian, and chrysoprase.
Writting Original articles by Navneet Gems and Minerals, the source of Wholesale Loose Chalcedony, Green Ony and Black Onyx and many more.Posted on Monday, November 7, 2011 - 11:44
Even though most Chalcedonies have been ignored for most of the past century, several varieties of Chalcedony have become more and more popular over the last two decades. Chalcedony chrysocolla, Chalcedony Holley and Chalcedony Mojave, Chalcedony blue agate, Chalcedony carnelian, and chrysoprase are increasingly in demand for jewelry. There is a very good reason for this upward spike. New sources of these agates have produced gems of such surpassing beauty that they have simply become impossible to ignore. American and European lapidary artists have made extensive use of these materials in gem carvings. A few years ago Town & Country magazine featured an article on blue agate attesting to the fact that chalcedony is enjoying a new surge in popularity.
The best example of the first three types mentioned is found in the United States. The last two are found in Africa and Australia. All are from sources that have been discovered in the last twenty years. So fairly new sources for Chalcedony Gemstone, a semi precious stone.
Writting Original articles by Navneet Gems and Minerals, the source of Wholesale Chalcedony from Bangkok.Posted on Monday, November 7, 2011 - 11:32
Unlike crystalline quartz materials such as amethyst, which is a single crystal, this species of Chalcedony quartz is composed of tiny interlocking microscopic fibers. For this reason it is also called cryptocrystalline (hidden crystal) quartz.
Writting Original articles by Navneet Gems and Minerals, the source of Semi-Precious and Precious Gemstones from BangkokPosted on Monday, November 7, 2011 - 11:26