Glossary of Faceting Terms and Definitions


This compilation of faceting terms and definitions has been generously provided by International Gem Society (IGS) member Tom Mitchell.  He is the author of Faceting 1, Learn The Fine Art of Gem Faceting, it’s Easy.

Acetone

A solvent that can be used to dissolve dop wax or help to release super glue.

Alignment

Positioning the stone so that the crown break facets match up with the pavilion break facets at the girdle after transferring the stone.

Analog vs Digital Angle Scales

Some newer faceting machines have digital angle scales that allow the quill to be adjusted to a 100th of a degree, which corresponds with modern gem designs produced in typical GemCad format. The average machine has a protractor or analog angle dial which reads to 1 degree with a vernier scale which allows further adjustment to a 10th of a degree.

Axis

This refers to 1) the direction of crystal growth in gem material, such as the A-axis or width, the B-axis or depth and the C-axis or length. In some tourmalines the C-axis may be blocked, also referred to as “closed,” which prevents light from passing through it, or; 2) in a symmetrically cut stone, it refers …

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Content Length 4280 words
Reading time 21 min 24 sec

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  • Acetone
  • Alignment
  • Analog vs Digital Angle Scales
  • Axis
  • Boule
  • Brilliance
  • Caliper
  • CAM and CLAM
  • Carat
  • Carat Scale
  • Ceramic Lap
  • Charging
  • Cheating
  • Cleavage and Fracture
  • Color Absorption
  • Color Change
  • Colored Stones
  • Color Zoning
  • Crown
  • Critical Angle
  • Culet
  • Cutter or Polisher
  • Cutting
  • Depth
  • Denatured Alcohol
  • Diamond
  • Diamond Slurry
  • Dispersion of Light
  • Dop
  • Dop Rack
  • Dop Wax
  • Dopping
  • Double Refraction
  • Eye Clear or Eye Clean
  • Facet
  • Faceting
  • Faceting Head
  • Faceter
  • Fashioning
  • Flame Source
  • Flaws
  • Gem
  • Gem Jars
  • Gem Papers
  • Girdle
  • Graspers or Gem Holders
  • Greenway Polishing Lap
  • Grit
  • Half-Light
  • Hardness
  • Hard Stop
  • Heel
  • Index Gear
  • Index Number
  • Initialize
  • Keel
  • Kerf
  • Lap
  • Lapidary
  • Last Lap
  • Light
  • Lightning Lap
  • Loupe
  • Loupe-Visible or Loupe-Clean
  • Main Facets
  • Marking Pen, Pencil, or Scribe
  • Mast
  • Master Lap
  • Meet
  • Meetpoint
  • MEK
  • Mixed Cut
  • Mohs Scale
  • Natural Rough
  • Optivisor
  • Pavilion
  • Plan View
  • Platen or Turntable
  • Point
  • Polish
  • Polishing a Window
  • Pre-form
  • Protractor or Analog Angle Indicator
  • Precious and Semi-Precious
  • Quill
  • Refractol
  • Refraction
  • Refractive Index
  • Rough
  • Scintillation
  • Shape
  • Side View
  • Single Cut
  • Soft Stop
  • Specific Gravity
  • Splash Guard or Fence
  • SRB
  • Step Facet
  • Sticky Dop™
  • Swarf
  • Symmetry
  • Synthetic Stones
  • Table
  • Table Adaptor or 45 Degree Table Adaptor
  • Tier
  • Toppers
  • Transfer Jig
  • Ultra Lap
  • Vernier Scale
  • Vertical Axis

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