Saturday, August 20, 2011

Lapidary and Gemstones - unusual finds !

MAW Sit Sit --- A beautiful green colored stone that looks like fine quality jade, which makes sense since one of the constituents that make up Maw Sit Sit is jadeite. It is a metamorphic rock that was formed when higher pressure changed a formation of igneous rocks. The formation had a lot of chromium based minerals such as chromite and chrome rich jadeite, which accounts for the color. Maw Sit Sit has been pretty rare on the market, but more and more of it is appearing as time goes by.

This is a wonderful example of what the gemstone world can offer with an unusual name from a small place that no one has heard of ... until they named a gemstone after it, from a place called Maw Sit Sit in upper Myanmar. Maw sit sit was first identified by the late Dr. Eduard Gubelin in 1963 and named after the village close to the site where it was found. It is currently on the list for non-importation into the USA along with Myanmar (Burma) Rubies unless one can show a purchase date before the law went into effect.


Zoisite Conglomeriate --- This beautiful combination of Ruby embedded in a matrix of green and black Zoisite is also known as Anyolite. This stone has wonderful red Ruby crystal structure embedded in a natural matrix of green and black Zoisite. It is strikingly dramatic, beautiful and hard to come by. Bright and bold opposite colors contrast to form exquisite patterns people love to look at. Although Anyolite is many times advertised as a variety of Zoisite from Kenya and Tanzania, Anyolite is actually a metamorphic rock composed of intergrown green Zoisite crystals, black Tschermakite cystals, and Ruby crystals. It is said to be named after the Maasai word 'anyoli', meaning "green." The contrasting colours make Anyolite a popular material for sculptures and other decorative objects. It was first discovered at the Mundarara Mine, near Longido, Tanzania in 1954. Much of the material now being called Zoisite Conglomeriate nows comes out of South Africa. Anyolite is also referred to as Ruby in Zoisite or Tanganyika Artstone when smaller amounts of the black Tschermakite crystals are present. Do NOT confuse Ruby if Zoisite with Fushite, especially when it is Ruby in Fushite).


Septarian Concretion --- Concretions are masses of mineral matter formed when minerals in water are deposited about a nucleus (such as a leaf or shell or other particle) forming a rounded mass whose composition or cement is usually different from the surrounding rock. This can occur at the time of deposition, shortly thereafter, or after the sediment has hardened. Generally, concretions are harder than the rocks around them; therefore, over time the concretions can weather out of the surrounding rocks. Concretions are found world wide, but some of the best come from Wyoming and Kansas. These are formed from any of a number of minerals, including calcite, limonite, barite, pyrite, or silica. They vary widely in shape and size. The smallest are oolites, which can be smaller than the head of a pin. At the other end of the spectrum are the huge spherical Septarian Concretions, the largest of which have diameters of 20 feet or more. The exteriors of septarian concretions are crisscrossed by a network of ridges, giving some of them the appearance of a turtle shell. Geologists think they were formed by the shrinkage of concretions, which caused cracks to form, followed by the deposition of the various such minerals. When the concretions are exposed to weathering, the softer parts between the mineral-filled cracks are eroded and the cracks extend above the surface of the concretion, like ridges or little walls. When cut and polished, they make interesting stones for jewelry, as long as they are well protected. .