Extracts of Articles

Amethyst The art of lapidary is to place color correctly in order to make homogeneous tone of cut stone. The distribution of color in a cut stone is observed simply by immersing it in water contained in a transparent container and colourless. Corundum Corundum is composed of pure alumina; its colouring is due to metallic oxide traces or inclusions. Gems are generally found in alluvium, but come either from basaltic slag, or from metamorphosed limestone.

Tourmaline Coloured tourmalines are related to sodolithic pegmatite. One distinguishes two principal types of tourmalines: hexagonal type and triangular one.

The Mine of Anjanabonoina, located in high plateaus, produced rubellites, green tourmalines, and a variety of rare stones. Garnet

The Besafotra river carry spessartites on several kilometers from their source, doubtless a sodolitic pegmatite. Tanety "grounds bordering river," are also object of orange garnet's fever. Malaya Garnet Discovery This marvellous chromium-spessartite garnet from Madagascar was discovered in its bedrock in 1996. This discovery remains exceptional by quality of its product and also by fact that it was second deposit in world to deliver this type of Malaya garnet. Crystalline Systems 7 systems of crystallization: There are 32 possibilities of combinations of elements of symmetry. All geometrical operations which cause a repetition of pattern are called operations of symmetry. Cutting Styles

Table, Crown, Girdle, Pavilion, Culet. Fancy Styles Back to Top Shield Cut, Trillant Cut.

Cutting Characteristics When a stone is cut according to good proportions, light is reflected from one facet to another and arises by top.

Gemology

De Beers sued by head of Diamond Bourse

Derek Parsons, president of Diamond Bourse of Southeast United States has filed a lawsuit against De Beers, on charge of company's disregard of American competition law. Their Supplier of Choice policy puts American dealers at a disadvantage. The suit was not launched on behalf of Miami bourse but on behalf of diamond dealers in America, condemning criteria on which De Beers makes sales – they would sell only to their sightholders, discouraging non-sightholders and keeping prices artificially high at a non-competitive level.

Diamond mining expands

De Beers holds control of only 50% of roughs market

Diamond rising prices have stimulated exploration and mining in more countries such as Canada, Russia, Angola, India, Brazil. Nevertheless, about 40% of diamonds still come from Botswana and South Africa. De Beers' control on rough diamond market was declared to have decreased from 70% to about 50%. Canada, Russia and West and Central Africa are considered by specialists an important potential diamond source. India and Brazil are prospected by geologists also due to fact that they are known to have been a diamond source in past.

The largest diamond reserve of Africa lives in extreme poverty

Although fourth largest producer in world by value and holder of largest diamond reserves in Africa. Angola's per capita gross national income GNI is estimated at $650 per annum. People' s main means of subsistence is agriculture. The diamond sector has been seriously affected by long war and by gem smuggling. Yet it still represents a very important potential driver of economic development. Since 2002, when conflict between government and UNITA rebel movement ended, developing sector has become a national priority and government has already made changes to diamond sector regulations. Serious redevelopment and investment is needed in this area. At present, artisanal mining operates in Angola and it brings very little economic benefit to local communities.

Increasing conflict in Russia between diamond cutters and miners