Science of nothing

The diamond trade thrives on pseudo science - the more "scientific" and complicated the terms are, the better it is for a trade that is build around simple exchange: "You give us your house down-payment; we get you a fleck of a shiny crystal."

The way to do it is simple: blindside the customer with a barrage of terms they never heard before, provide elaborate "scientific" explanation coupled with the use of "patented" appliances and the poor soul will be happy to hand his wallet.

Understanding and selecting diamond is easier than you are made to think. Here we provide a quick overview of some terms you will hear often. Some of them are useful, some unnecessary, some are borderline scam.

In addition to the 4C's, there are a few more terms often used by diamond dealers to further confuse buyers.

Dispersion

The separation of light into colors by refraction or diffraction with the formation of a spectrum. In diamonds, the process of refraction will cause a ray of light exiting to split into distinctly perceptible prismatic colors.

Much of the beauty of diamonds depends on dispersion, which is significantly lower in other colorless stones, such as rock-crystal, topaz, colorless sapphire, cubic zirconium, etc. The refraction index of diamonds is relatively high. Among other stones with high refractive index are demantoid garnet and moissanite.

ASET test

This is a “tool” developed to measure the “quality” of a diamond based on its interplay with light.  Giving off different colors when the diamond is placed into it, the tool positions the diamond on a quality scale. Blue, red, green, and black colors are shown depending on the angle degree from which the light hits the diamond. Red is the color that people think they want to see in the portrayed image from this tool.

This contraption is meant to quantify the beauty of a diamond – a task possible only in the eyes of a fool. Science and aesthetics go hand to hand. ASET test is not a science. It's an attempt to simplify and stupefy the science. As if the diamond speaks with the light, this machine is intended to wire tap the conversation.

Brilliance

This is a well understood property that would measure the amount of "sparkle" any particular stone exhibits.

In the days predating the Modern Brilliant cut it was a very important property. Older stones by virtue of having larger and fewer facets could not display as much brilliance as any modern cut. The facets were angled differently and therefore reflected light back to the observer fewer times.

Think of each facet as an individual mirror reflecting light. The more reflections are directed at your eyes, the more brilliant the stone is.

Logically it could be applied only to brilliant-cut stones but logic has never been a strong pursuit of the diamond trade.

Scintillation

A bogus property that is indistinguishable from brilliance and designed to confuse you further. It's commonly referred as "sparkle" and there are volumes of pseudo-scientific gibberish you can easily find on line.

Obviously the amount of scintillation depends on the lighting and the movement of the observer or a stone.

Fire

This one was definitely coined by someone with a severe case of ADD.

Initially meant to be synonomous with dispersion, fire is a simpleton's attribute of a diamond as a combination of dispersion and brilliance in a single word.

Before the invention of electricity diamonds were mostly worn to candlelit parties where a warm spectrum of live fire was reflecting and refracting to inspire awe and distract from the fact that every man has a powdered horse hair rug on his head.

Symmetry

This is a very important feature of a diamond cut. Like everything else in the world too much of a good thing is not necessarily great. After all, any item produced by  a machine by definition will have perfect symmetry.

For various reasons most round diamonds feature perfect symmetry. One might argue that these stones look too "machine made," artificial, devoid of a soul.

Triple X

Not an adult feature, this is shorthand for Excellent grade in three categories: Cut, Symmetry, and Polish. This title is "a must" for a diamond to be qualified as an "Ideal cut" (see below).

Ideal cut

A sales term assigned to a diamond by a sales person in an attempt to close a sale. In general it means, "This stone is so good, you can't find anything better" in sales-speak.

It could also mean that the stone has a specific set of characteristics - crown and pavilion angles, crown height, table percentage - all should be within a poorly defined range.

Depending on who you are talking to a stone might be classified as "Ideal cut" if it has 53% - 59% table for example.

However, it's the most useful shorthand for a modern diamond that has superior cut.

Hearts and Arrows

A gimmick designed to confuse the consumer into thinking that the symmetrical pattern visible through a special viewer is an indication of the particular stone's beauty. There are hundreds of different patterns of hearts and arrows. The appearance of these patterns is due to a unique combination of a stone's proportions and ideal symmetry. Hearts and arrows is a great sales tool to demonstrate a stone's symmetry to a customer. However, it will not make the stone any more valuable if you are trying to sell it.

Verdict - Cute but useless.