Yttrium Aluminum Garnet Faceting Information

Yttrium (YAG) is also known as various other names in the gemstone market today such as diamonite. This may also be used as a gemstone imitation.


Yttrium Aluminum Garnet (YAG)

YAG/yttriumColor: Wide range of colors available.
Moh's Hardness: 8.5
Refractive Index: 1.833
Critical Angle: 33.12°
Specific Gravity: 4.55
Cleavage: Imperfect
Fracture: Conchoidal
Dispersion: .028
Heat Sensitivity: Slight
Birefringence (double refraction): None
Crystal Structure: Isometric

Treatments: None

What I prefer to polishing with: Tin lap with Alumina oxide. Zinc laps with 8,000 pre-polish and 50,000 polish.

Jeff's Comments: Cuts and polishes like Garnet. It is quite pretty especially in clear and light colors.

Design Links: 4-Way Stop - This is great for saturated rough if you have a piece that will work in the shape.
Princess - Nice in about any material
Brilliant Pear - Good in any color


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.

Never Stop Learning

When you join the IGS community, you get trusted diamond & gemstone information when you need it.

Become a Member

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!