Monday, 22 April 2013

Introduction Synthetic Strontium titanate

Examples of Fabulite

SYNTHETIC STRONTIUM TITANATE (SrTio3)


Strontium titanate produced by a variant of the Verneuil method, using extra oxygen. It is wholly artificial, with no natural counterpart.

Crystal system 


Cubic

Appearance 


In the shape of a pedunculated pear or sausage, generally no more than 2.5 centimeters in diameter and about 10 centimeters long. It is transparent and colorless.

Physical properties 


It has rather a low hardness of 5.5, and is somewhat brittle. The density is 5.13 g/cm3. The refractive index is 2.41, which is almost equal to that of diamond. It has exceptional dispersion, of 0.19, which is only exceeded by synthetic rutile.

Production 


Considerable quantities were manufactured in the United States around 1955, but production is now very limited, as it has been replaced by other synthetic materials.

Fabulite (synthetic strontium titan-ate) 


Examples of FabuliteThis is one of several fanciful names coined for this artificial product issued on the market beginning in 1955. It appeared at the time to be a first-rate imitation of diamond, but after only a few years has been rendered almost obsolete by products with better characteristics (above all, hardness), which look more like diamond and cost less.

Appearance 


It has considerable luster, equal to that of diamond, when the facets and edges have not been dam-aged by use. Because of its exceptional dispersion, it looks highly iridescent in strong light. In diffuse light, it is perfectly colorless. It is singly refractive like diamond. The facet edges are often visibly damaged due to its brittleness and low hardness. It is always cut into brilliants.

Distinctive features 


When viewed with a lens from above in strong light the iridescence is characteristic, being more obvious than in diamond and little less than that of synthetic rutile. Not being strongly birefringent, it can immediately be distinguished from the latter. Obvious surface damage, particularly to the facet edges, is indicative of its low hardness. For the same reason, the facet edges are not sharp and the stone feels slippery to the touch.

Cost 


Higher than that of other, more recent and better imitations of diamond, but less than that of the most expensive synthetics, such as emerald

Writer – Curzio Cipriani and Alessandro Borelli

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