Reference Guides

The language
of cut stones.

Every term that appears on a cut page, explained fully. Read these before you shop — or use them as a reference when a grading report or sales sheet leaves you with questions.

Start Here 6 guides
Begin here
How to Read
a Cut Page
A walkthrough of this site
→
How to Read a GIA Grading Report
Every field explained, field by field
What a Grading Report Doesn't Say
The gaps every buyer should know
IGI vs GIA
Which cert to trust, and when
Facets
How facets work
Cut Popularity
What market share means
Cut Comparisons 5 guides
OvalvsRound
Size, bowtie & price gap
OvalvsCushion
Size, subtype & bowtie risk
PrincessvsRound
What the price gap actually reflects
CushionvsRound
Fire vs precision
EmeraldvsAsscher
Two step-cut silhouettes
Light Performance 7 guides
The Bowtie Effect
What it is & how to evaluate it
Brilliance
White light return
Fire
Spectral dispersion
Scintillation
Flash & sparkle pattern
Size per Carat
Face-up appearance
Clarity Concealment
How cuts hide inclusions
Fluorescence
UV emission & price impact
Cut Specifications & Grading 6 guides
Table Percentage
The top flat facet
Depth Percentage
Total stone height
Crown Angle
Brilliance vs. fire balance
GIA Cut Grade
Excellent to Poor
Polish & Symmetry
Surface & facet alignment
Graded Cuts
Which cuts GIA grades
Budget & Value 4 guides
The Round Premium
Why rounds cost more
Fancy Shapes
Why they cost less
Lab Grown
The neutral breakdown
Moissanite vs Diamond
An honest comparison
Named Originators 6 guides
Marcel Tolkowsky
Round brilliant
1919
Joseph Asscher
Asscher cut
1902
Lazare Kaplan
Oval brilliant
1957
Lodewyk van Berquem
Early faceting
1458
Ambar & Perlman
Princess cut
1979
Henry Morse
American ideal cut
1860s