© 2004 gggems.com All rights reserved.
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.
Microscopes: binocular one, i.e. to double objective is best adapted for gemology. The microscope is of first importance in detection of counterfeits. Indeed, study of inclusions which stone can contain is a practical means to identify gems while explaining to a certain extent conditions under which they were formed in nature. Size & Weight Back to Top Sapphire, Ruby, Emerald. Madagascar gem safari