Reference Charts and Materials

Commonly used charts for gemology and jewelry and lapidary.

Reference Charts and Materials

  • “Moissanite Enagement/Wedding Ring” by 3BL Media is licensed under CC By 2.0
    Diamond and Simulant Comparison Chart

    Properties Natural Diamond Type Ia Natural Diamond Type Ib Natural Diamond Type IIa Natural Diamond Type IIb Moissanite Cubic Zirconium RI 2.417 2.417 2.417 2.417 2.648 – 2.691 2.15 -…

  • 12-02-05_143654_M=B_R=8_S=4diamond-silverwhite-si-africa-29A4
    Diamond Look-a-like Comparison Chart

    One of the biggest challenges for a new gemologist is separating diamonds from their look-alikes. The keys to identifying these gems are specific gravity and birefringence. The following stones are arranged by specific gravity. Note that…

  • gem weight - brooch
    How to Estimate Gem Weight in a Jewelry Setting

    Although you can’t weigh a gemstone in a jewelry setting, you can get a close approximation of the gem weight by determining its volume.

  • cry2b.gif
    Gem Structure Chart

    Structure Crystal axes and Angles Optic Character Refractive Indexes Optic Sign Pleochroism Examples Amorphous No orderNo axes IsotropicSingly refractive 1 RI None None Opal, Amber, Glass, Plastic Isometric 1 axis…

  • osign2
    Cheat Sheets for Gemologists 

    Step 3: Practical Gemology Lesson 27 Back to syllabus Clarity Types Type I Usually eye clean Type II Usually included Type III Almost always included Aquamarine Chrysoberyl, yellow and green Heliodore Morganite…

  • List of False or Misleading Gemstone Names

    False Gemstone Name Actual Gemological Name Adelaide ruby Almandite African emerald Green fluorite Alaska diamond Rock crystal (quartz) American jade Green idocrase American ruby Pyrope or almandite (garnet)…


    Jewelers need to know how to determine how much gold is needed for a wax mold. Here are three methods for you: METAL METAL/WAX RATIO SILVER 10.5 – 1 GOLD 10K 13 – 1 GOLD 14K 14- 1 GOLD 18K 16 – 1 PLATINUM 22 -…

  • Select Gems Ordered By Density

    Gemstone Density Gold 15.5 -19.3 Thorianite 9.7 – 9.8 Silver 9.6 – 12.0 Algondonite 8.38 Bismutotantalite 8.15 – 8.89 Cinnabar 8.0 – 8.2 Stolzite 7.9 -…

  • Mohs hardness scale - tools
    The Mohs Hardness Scale And Chart For Select Gems

    The Mohs Hardness Scale 10 Diamond 9 Corundum 8 Topaz 7 Quartz 6 Feldspar 5 Apatite 4 Fluorite 3 Calcite 2 Gypsum 1 Talc Select Gems Ordered By Mohs…

  • Standard Gem Sizes Chart

    Purpose: Mass produced gem settings come in standard sizes. If a gem won’’t fit in a standard setting, a setting should be custom made. This involves much more labor and therefore expense. Bear this in mind when purchasing a gem, or selecting a cut…

  • Table of Gems Ordered By Crystal System

  • Table of Refractive Index and Double Refraction of Gems

    Gemstone Refractive Index Double Refraction Hematite 2.940 – 3.220 0.287 Cinnabar 2.905 – 3.256 0.351 Proustite 2.881 – 3.084 0.203 Pyrargyrite 2.88 – 3.08 0.200 Cuprite 2.849 none Rutile 2.616 -…

  • Weights and Measures Conversion Chart

    1″ = 25.4 mm 1 mm =…

  • Birthstone Chart


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