Blue spinel

 

The blue variety of noble spinel was in the past much les~ widely known and appreciated than the red variety. Appearance The finest specimens, though rare, have bright blue color comparable to that of some sapphires and are very attractive, lustrous, and transparent. Almost a, pleasing are equally lustrous light violet-blue stones, re assembling some sapphires of the same color. Most blue spinels, however, are a deep, dull color tending to soot. gray, albeit with a violet tinge; and their luster and transparency are marred by a touch of cloudiness. These are often cut quite shallow, in an attempt to lighten the color usually with modest results. Like sapphires, they are normally given a mixed, oval cut.

Distinctive features Fine blue spinels are hard to distir guish at first sight from sapphires of a similar color. The, latter may display clear pleochroism, but this is not always the case, particularly with medium to light blue specimen, Hence lack of pleochroism is not a sure distinction. B. there is a marked variation in density, which is easy to establish, and the refractive indices are also difference Cloudy, deep-blue spinels, on the other hand, are quite distinctive.

Occurrence Blue spinel is mainly found in the gem gravels of Sri Lanka and, rarely, in Burma.

Value Attractively colored blue stones, which are rare and not very large, are worth much the same as the red variety, whereas the fairly common, cloudy, less attractive stones are very modestly priced.

Simulants and synthetics Like synthetic ruby, dark-blue synthetic spinel was one of the first synthetic gems to be manufactured, at the beginning of the twentieth century Synthetic stones were not intended to imitate natural spinel, but the much more precious sapphire, after early unsuccessful attempts to synthesize the latter.

Synthetic spinet was colored by adding cobalt (in natural sapphire, the coloring agent is iron). As a result, if one of these stones is exposed to strong, tungsten light, it emits strange gleams of red fluorescence of a type not seen ir any other stone, and this can be a valuable aid to recognition. Light-blue synthetic spinel is also produced in considerable quantities, to simulate another gem: aquamarine

 

 

Copyright 2005 © Gemstone Jewelry

eXTReMe Tracker

HOME | ABOUT US | PRODUCTS | GEMSTONE | SERVICES | CONTACT US

We only provide the most brilliant natural Precious Gemstones and diamonds, highest quality pearls and rare precious gems are combined and set with 18ct gold rings & Sterling Silver Jewelry chains to create the finest and most elegant designer jewelry.