Gem Information Vol.37.38 on 23rd July

New issue of our Gem Information Vol.37,38 is published on 23rd July 2008. Briefly introduce the contents.

1) Copper diffusion treatment of andesine and new mine of Tibet
1] Copper diffusion treatment of andesine
2] “Holy” andesine from Tibet
3] Current situation of andesine identification
2) Rhodolite garnet from Madagascar
3) The rare and rarerSpessartine Garnet
4) Transparent rhodonite from Madagascar
5) Mysterious hackmanite
6) Tugtupite, red hackmanite?
7) EDXRF is installed to our laboratory
8) Rare stone collection Vol.17
81) Chondrodite 82) Cleiophane 83) Creedite
84) Musgravite 85) Poudretteite
9) 75 years history of Deutsche Gemmologische Gesellschaft
1] 75th anniversary of D.Gem.G
2] 14 special lectures at the ceremony
3] 75 years history of D.Gem.G

The detailed explanation will continue. Please click beneath link.

Copper diffusion treatment of andesine and new mine of Tibet

Red and green plagioclase feldspar from Congo hit the market around 2000 and same kind of stones from China around 2004. Recently, we got two types of treated rough stones which are internally diffused with its color agent, copper, from Thailand and China. One type shows outer rim with spotted color and the other oppositely shows color concentration at its center. At the same time, we had news that a new mine of natural red and green color andesine / labradorite from Lhasa, Tibet. However still we do not find the clear difference to identify the natural color and treated color, but we try our best to find them with other gem laboratories.
*) if more detailed information is needed, please contact us with E-mail.

The rare and rarerSpessartine Garnet
Garnet has many varieties with its solid solution group. But the production of spessartine garnet decrease these days. This time, we checked again the features of its origins of Sri Lanka, USA CA, Namibia, Nigeria, Germany and Malaya Garnet from Kenya.

Hackmanite and tugtupite change their color with UV
Hackmanite is popular for its color changing effect with UV light. The stone from each origin has some features in the exam of FT-IR, UV-Vis Spectrophotometer, EXDRF and its
color-change effect. Especially the Hackmanite from Myanmar shows strong color change. If it is used just like a UV detector, it will be an interesting function on daily wearable jewelry.

Hackmanite is famous as color changing stone with UV light. But tugtupite also has such color changing effects and unique beauty. This time we examined a new stone which was ordered for identification and our collections and checked the features of these stones.

Transparent Rhodonite from Madagascar
Recently, some transparent rhodonites from Madagascar are seen in the market. Before those transparent stones were taken only from Australia and Brazil. But current ones are said to be from Madagascar. We checked the features of Madagascar rhodonite.

75th Aniversary of D.Gem.G
Deutsche Gemmologische Gesellschaft (German Gemmological Association) celebrated its 75th anniversary in June 2007. The world leading researchers and dealers joined the ceremony from all over the world and had special lectures about newest topics of gemstones. Needless to say,
the lectures are exciting, but what was impressive to me was the close relationship of laboratory, DGemG, and gem dealers in Idar-Oberstein. Both of them work very closely with sharing the same goal of healthy development of gemstone industry.