Brilliancy: The total amount of light reflected from both the interior and exterior surfaces of a gemstone. The amount of brilliancy also depends on the cutting, transparency, facet angles, proportions and polish.
Brilliancy
The total amount of white light returned to the viewer by a gem. This includes internal and external reflections.
Brilliancy The intensity of the internal and external reflections of white light to the eye from a diamond or other gem in the face-up position.
Brilliancy: a gemstone needs to be cut with correct crown and pavilion angles for light to be reflected back up through the crown and appear bright. Shallow and deep stones will leak light through the pavilion causing loss of brilliance.
Therefore it is only when a gem possesses to the nth degree, first, hardness - the principal qualification - then brilliancy, then beauty, then durability, then rarity, that it is given the brevet of preciousness.
Look for well-cut stones that have lots of brilliancy, which are usually more round in shape. Be careful if the shape is to free-form. If not round or pear-shaped, they can have a "baked potato" effect where they lose brilliancy.
Small differences of angle make considerable differences in the brilliancy of cut stones. The prevailing tendency to cut nearly all diamonds round depends largely upon the above facts.
The colour however, is by no means everything; semi-transparency, brilliancy, and hardness are also essential. Stone which satisfies these four conditions is very rare.
American Cut - Those proportions and facet angles calculated mathematically by Marcel Tolkowsky to produce maximum brilliancy consistent with a high degree of fire in a round diamond brilliant are considered by many diamond men to constitute the ...
To make a wise choice, you must be able to judge their color, flaws, transparency and brilliancy. This guide will show you how.
Little effect on the brilliancy of a stone.
I2 (imperfect 2) - More and/or larger inclusions and surface blemishes easily seen without 10x magnification. Some diminished brilliancy within stone.
This enhances the brilliancy of the stone, by reflecting back as much light as possible. It is commonly seen in costume jewelry.
Aquamarine does not loose its brilliancy in artificial lights, but was still not very highly valued.
Origin of name, overview classic "Aquamarine localities" and colors. Aquamarine Mine (photo) Mitchell County, N.C.
GLASSY. Applied to diamonds which lack brilliancy.
GOLCONDA. Ancient and famous group of diamond mines on the Kistna River, India, where were found the Koh-i-noor and other world-famous diamonds.
GOLCONDAS. Diamonds from India.
Its value derives from three important properties: its hardness; its brilliancy which results from its high index of refraction; and his fire which results from its strong dispersion.
Good proportions are important to give peridot his full brilliancy and special attention should be given to the quality of the polish.
Chanthaburi
Consult list of gems available on the Chanthaburi market...
An exceedingly shallow diamond with a noticeable lack of brilliancy. The girdle is usually reflected under the table edge.
Flaw
A term used to describe any external or internal imperfection in a diamond.
“The cause of this must be sought not only in their coloring and brilliancy but also their durability.
A method of coating the back of a stone with silver, gold, or colored foil to enhance the brilliancy of the stone.
French Wire
A curved wire that passes through the pierced earlobe and has a catch closure. Used mostly in dangling earrings.
Marcel Tolkowsky's mathematically calculated ideal proportions and facet angles, to produce maximum brilliancy consistent with a high degree of fire in a round brilliant gemstone. This is known as American Cut or Ideal Cut.
Amethyst ...
European Cut
European Cut is an older style of round cut that has less facets and less brilliancy than present day round cut stones.
Eye Pin
Eye Pin is a tool that is used to link beads together.
In 1958, the stone was again recut by it's owners, Baumgold Bros., New York City, to improve the proportions and increase brilliancy.
It now weighs 55.09 carats and is valued by the firm at $500,000, but is probably worth considerably more.
F
FACET - One of the small, flat surfaces that is polished on a gemstone to increase brilliancy and beauty. A round brilliant cut gemstone has a total of 57 or 58 facets.
Buff top
A stone cut into a flat dome shape with no facets, the bottom is usually facetted for better brilliancy. Many time the crown from the facetted stone is polished to a buff.
Although the brilliant style was devised to give maximum brilliancy and fire, many stones cut in this fashion do not have ideal proportions or angles for that purpose.
A form of step cutting, this cut is favored for diamonds and emeralds, as well as many other stones, when the principle purpose is to enhance color rather than brilliancy. Sometimes, it is also used to emphasize the absence of color in diamonds.
some of the beauty is sacrificed to minimize weight loss to get a larger finished diamond. The American Gemological Society's Ideal Specifications rate the cut quality on a scale from 0 to 10, 0 being the perfectly cut diamond for maximum brilliancy.
cement, then pressing it against a revolving cast iron disk, on a scaife, or lap that has been "charged" with diamond dust. During this faceting stage the angles of each facet must be cut to an exacting standard in order to yield maximum brilliancy, ...
 See also: Stone, Cut, Diamond, Gem, Rough
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