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How to Talk Like a Gemologist and Not Get Ripped Off

Frank Darling’s glossary of confusing words and frequently misunderstood diamond terminology.

If you’ve started your search for an engagement ring, you’ve probably sat down with a salesperson or two and pretended to understand what the heck VVS2 could possibly mean. Or maybe it was fluorescence? Brace yourself, because it gets worse before it gets better. Diamond terminology is dense, technical and confusing. But there is hope, and today it comes in the form of a glossary.

In the diamond district, “Diamond sellers, or diamantaires, deploy an extensive nomenclature of technical terms to describe their wares — not just the famous Four C’s of color, clarity, cut and carat weight, but also dimensions, fluorescence, inclusions (flaws), polish and symmetry.” NYT

Those technical terms exist to help diamond sellers grade and price their diamonds. But, when used incorrectly, they can also make it clear to a diamond seller that you don’t know the lingo. Let’s break down the most commonly confusing diamond terminology and phrases so when they come up in conversation you can keep your chin up and confidently say you’re not going to pay for an extremely thick girdle, and know what it means.


Baguette: Rectangular stones that look similar to emerald cut diamonds with fewer facets. Often used as side stones, or in eternity bands. Here a .5 carat baguette is bar set east-west into a solitaire setting.

An east west baguette solitaire

Shown: Billie. No. 5 in yellow gold with a 1/2 carat baguette. Shop the look.

Brilliant cut: A type of diamond cut that maximizes brilliance and light return through a series of facets. Round, oval, pear and marquise cut diamonds are all brilliant cuts.

A round brilliant diamond set in a platinum bezel setting. The best diamond shape for sparkle.

Shown: Parker No. 7 in white gold with a 1 carat diamond. Shop the look.

Champagne Diamonds: Brown diamonds with a hint of yellow that look like champagne. Cheaper and more available than colorless diamonds. Diamond sellers often make higher profit off of Champagne diamonds due to their lower cost.

Old mine cut champagne diamond

Clarity Enhanced: Diamonds that have been artificially treated to improve their clarity grade and sell for more money. This can be seen on a diamond certificate.

Cognac Diamonds: Deep brown diamonds with a hint of orange that look like a bottle of, you guessed it, cognac. Like Champagne diamonds, these are much less rare, and much lower value than white diamonds.

A rough cognac diamond

Shown: A Rough Cognac Diamond | Credit: Worthpoint

Color Enhanced: Diamonds that have been artificially treated to appear a different color, usually whiter, and sell for more money. This can be seen on a diamond certificate. Learn more.

Fancy Diamonds: Diamonds cut into shapes other than round.

Oval bezel solitaire in 18K yellow gold

Shown: Parker No. 8 in yellow gold. Shop the look.

Recycled Diamonds: Diamonds that have been sold once before and are being sold again. They may or may not have been re-cut from an antique or less desirable shape into a more popular shape. Learn more.

An old miner cognac diamond

French Baguettes: Similar to a regular baguette but with additional facets for added brilliance.

Lab-grown diamonds: Lab-grown diamonds are diamonds that are grown in a lab under high temperature and high pressure. Lab-grown diamonds are optically, physically and chemically identical to mined diamonds. Lab-grown diamonds are real diamonds, as ruled by the FTC. Search lab grown diamonds.

Melee: Pronounced Melly, from mêlé, French for “mixed”. These are smaller diamonds used as accent stones on a band and in halos that surround a center stone. Learn more.


“20 pointer”: .2 carats. Each point is 1/100 of a carat.

Eye-clean: Diamond terminology used to describe when a diamond doesn’t display any inclusions to the naked eye.

Certification: A grading report that accompanies a lab-grown or mined diamond and speaks to its quality. Diamond certificates usually include the four C’s. Frank Darling works exclusively with GIA, IGI and GCAL certified stones. Learn more.

Fisheye: A flat stone with no sparkle.

CVD: A method of producing lab-grown or lab-created diamonds. Learn more.

HPHT: One method of producing lab-grown diamonds. Learn more.

Karat: The unit of measure of gold. 

Loupe: A small handheld 10x magnifying glass through which to look at diamonds.

On memo: A term used by jewelers and retailers when they borrow a stone from a wholesaler on consignment and without paying for it first. Usually, 2-3 stones can be borrowed and put on memo at any one time.

Spready: A diamond that is cut more shallow and looks larger than its carat weight as a result.

Sterling Silver: Silver that contains a minimum of 92.5% silver.

The rap sheet: A price index developed by Martin Rappaport that, in place of a true price index, is widely used as the basis for buying and selling stones. Established in 1978 and updated once weekly on Thursday, the rap reflects high-cash asking prices for very good or ideal cut stones. Prices are referred to “off the rap,” or back or 10 back, which indicates a 10% discount off the listed price.

What’s the rap: What’s the listed price.


Bowtie: A black bowtie shape that characterizes poorly cut pears, ovals, and marquise diamonds.

Shown: An oval diamond with a bad bowtie.

Brilliance:  A scientific measurement of sparkle.

Carat: How much a diamond weighs. Our carat weight diagram.

Carat diagram for diamonds

Color: How white a diamond appears.

Color diagram for diamonds

Crown: The top of the diamond.

Culet: The bottom point of the diamond.

Facet: A flat polished surface on a diamond.

Fire: The colored a diamond reflects.

Fluorescence: A soft blue, white or yellowish glow a diamond emits under ultraviolet light i.e sunlight. Learn more.

Flourescent diamond diagram

Girdle: The thick band that runs around the middle of the diamond and separates the crown from the pavilion.

Inclusions: A diamonds imperfections.

A matched pair of triangles with visible inclusions

Shown: An included pair of triangles. Credit: Rough Diamond World

Polish: How smooth a diamond’s surface is.

Symmetry: A measure of how identical one side of a diamond is to the other. Learn more.


Prong: A piece of metal that holds the diamond in place. Settings usually have four or six prongs. Six prong settings are better for diamonds over 1-carat weight.

Bar set: A metal bar that holds two stones in place. Bar settings run perpendicular to the band and are often used for eternity bands.

Mason No. 5 a bar set triangle diamond in 18K yellow gold.

Shown: A bar set triangle diamond. Shop the look.

Bezel Set: A thin rim of metal that wraps around the girdle of a diamond to hold it in place. More secure than a prong setting.

Parker No. 1 a bezel set Asscher diamond

Shown: A bezel set Asscher diamond. Shop the look.

Cathedral setting:  A type of setting in which the band arches up towards the center stone similar to the buttresses on a cathedral.

An east-west marquise ring

Shown: An east-west marquise set in a cathedral setting. Shop the look.

Cluster: Many smaller diamonds clustered together to look like a larger diamond.

A cluster diamond ring in yellow gold

Shown: A cluster of round diamonds. Shop the look.

Channel Setting: A style of setting in which the stones are laid into a channel and sit flush with the band. Channel settings are known for their smooth finish.

Billie No. 1 Baguette Channel Band in 18K Yellow Gold

Shown: A channel set baguette eternity band. Shop the look.

Halo: A ring of small stones that encircle a diamond. Halo designs are engineered to make the center stone appear larger.

Oval halo in platinum

Shown: An oval diamond in a halo setting. Shop the look.

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