Properties of Diamond Simulants
Diamond simulants often appear in jewelry, as side stones and accents as well as centerpieces. Identifying these lookalike materials, whether…
Using Your Spectroscope
Step 3: Practical Gemology Lesson 3 Back to syllabus Sometimes, refractive index (RI) and specific gravity (SG) readings aren’t enough…
How to Measure an “Over The Limit” Refractive Index
A gemstone with a refractive index (RI) reading that exceeds 1.81 is said to be “over the limit” (OTL). Low-cost refractometers can’t…
Gem Formation: How are Gemstones Created?
Most gems form naturally as minerals within the Earth. Most form as crystals, solids whose atoms are arranged in highly ordered repeating patterns…
The Optical Properties of Gemstones
We tend to take light for granted. It’s such a common thing we experience every day. Rarely do we think of the scientific definition of light…
The Physical Properties of Gemstones
Step 2: Advanced Gemology Lesson 2 Back to syllabus The optical properties of gems attract our eyes and can give a cut stone a unique character. However,…
Jewelers’ Pricing Survey
Step 6: Appraising Lesson 4 Back to syllabus The International Gem Society (IGS) conducted a jewelers pricing survey in 2002 and 2012. Over those…
Identifying Synthetic Gems
Distinguishing natural from synthetic gems is a critical skill for gemologists. It could mean the difference between valuing a gemstone at thousands…
Identifying Synthetic Diamonds
Step 5: Advanced Gem Information Lesson 2 Back to syllabus Synthetic diamonds aren’t new. General Electric (GE) has been making them since…
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