Diamond Glossary

The knowledge and more information you have the better diamond purchase you will make. Here are a number of diamond terms that are used by jewelers to describe diamonds and which appear on diamond grading reports.

L:

Laser-Drill Holes:
One of the few man-made inclusions that can occur inside a diamond. Why on earth would anyone want to drill holes into a perfectly good diamond? It may seem counter-intuitive, but drilling this type of hole into a diamond can actually raise its clarity grade. In some diamonds, the clarity grade may be determined mainly by the presence of just one or two dark included crystals in a diamond that is otherwise relatively free of inclusions. In certain circumstances, the diamond cutter will decide to use a procedure to remove the dark inclusions and, hopefully, increase the clarity of the diamond. First, a hole is precisely made with state-of-the-art equipment; it extends no further than it needs to, and its width is so small (about the size of a pinpoint) that a loupe or microscope is usually required to detect it. Next, a strong acid solution is forced into the new hole.

Since diamonds are resistant to acids, the solution actually dissolves the included crystal while leaving the diamond completely unharmed. The end result is a more transparent diamond. The structural stability of the diamond is not compromised in any way by this hole, and the process is permanent.

Length-to-width ratio:
A comparison of how much longer a diamond is than it is wide. It is used to analyze the outline of fancy shapes only; it is never applied to round diamonds. There's really no such thing as an 'ideal' ratio; it's simply a matter of personal aesthetic preferences. For example, while many people are told that a 2 to 1 ratio is best for a marquise, most people actually tend to prefer a ratio of around 1.80 to 1 when they actually look at marquises. And though the standard accepted range for the length-to- width ratio of a marquise generally falls between 1.70 to 1 and 2.05 to 1, there are customers who insist on having 'fatter' marquises of about 1.60 to 1 and other customers who want longer, thinner marquises of 2.25 to 1.

Loupe:
Magnifying glass usually of 10X.

Laser Indentification:
Microscopical small inscription by a laser on a diamond for indentification. Can be the diamond certificate number, a message, brandname and number or otherwise.

Laser Drilling:
An artificial clarity enhancement process in which a laser is used to drill to an inclusion within a diamond which is then bleached to appear white.

Laser Inscription:
A technique to hallmark, brand or inscribe the edge of a diamond with a serial number or other inscription.

Light Yellow:
A trade term used by some dealers to cover a wide range of colors in the low end of the diamond color-grading scale. Stones in the broad classification show a very obvious yellow tint to the unaided eye.

Lot:
A group of rough diamonds offered for sale by the Diamond Trading Co. to firms invited to view its sights. A lot usually includes a wide variety of material. Also applied by diamond merchants to their regroupings of these diamonds according to color, make, and comparative freedom from imperfections after fashioning.

Luster:
The quality of reflected and refracted light from the surface of a gemstone or pearl.

Laser Cut:
Using a laser to fashion the diamond's eventual shape, allowing cuts across the growth plains, thus permitting odd shapes such as letters, horse heads etc.

Leveridge Gauge:
Tool used to measure the precise dimensions of a mounted or un-mounted stone.

Lively Stone:
A stone with good brilliance and luster.

Loupe Clean:
When viewed under magnification 10X, a stone is considered loupe clean if no imperfections are seen.

Lower Girdle Facet:
Triangular shaped facets, located on the pavilion.

Lower Main Facet:
Eight, four sided facets meet at the center to form the culet (syn. 'Pavillion facet')

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