Emerald Faceting Information
Practical tips on Emerald Facet / Faceting Information. Covers Emerald Facet / Faceting Information related issues, news, research, tips, and guide.
Emerald (Beryl)
Color: Green
Mohs Hardness: 7.5-8
Refractive Index: 1.57-1.60
Critical Angle: 39.87°
Specific Gravity: 2.65-2.75
Cleavage: None
Fracture: Conchoidal, tough
Dispersion: 0.014
Heat Sensitivity: Yes, especially depending on treatments
Dichroism:Weak
Birefringence (double refraction): Weak (0.006-0.009)
Crystal Structure: Hexagonal
Treatments: Almost all emeralds are treated to improve color and durability. Assume that any emerald you see is treated. I personally do not agree with a lot of the treatments used on emeralds. Here is an article on emerald treatments and my opinion on them.
Are all Emeralds treated and what is your opinion?
What I prefer to polishing with: Cerium oxide with a Spectra Ultralap.
Jeff's Comments: I seldom cut emeralds, most of the rough is low quality in my opinion and I do not like to cut oiled, or opticoned rough. If you want to cut some for the color, I suggest cutting man-made emerald.
Design Notes: Mostly emerald cuts and step cuts because the crystals are usually small long and narrow.
Design Links: Signature #4 - This is one of my favorite cuts in beryl
Blue Ice - Designed for very long crystals
Jeff R. Graham
The late Jeff Graham was a prolific faceter, creator of many original faceting designs, and the author of several highly-regarded instructional faceting books such as Gram Faceting Designs.
Related Articles
Emerald Value, Price, and Jewelry Information
Seven Famous Emeralds and Their Stories
Emerald Origins: History and Identification
Emerald Transformation: Cleaning and Recutting a Natural Emerald
Latest Articles
Table of Gems Ordered by Crystal System
Mineral Cleavage Testing: A Practical Guide
Axinite Value, Price, and Jewelry Information
Introduction to Native Elements
Never Stop Learning
When you join the IGS community, you get trusted diamond & gemstone information when you need it.
Get Gemology Insights
Get started with the International Gem Society’s free guide to gemstone identification. Join our weekly newsletter & get a free copy of the Gem ID Checklist!