Understanding
Gemstones
A field guide to the terms, grades, and treatments you'll encounter on every Gemplore listing.
Gemstone Categories
Ruby
Pigeon blood to vivid red
Read the Guide →Sapphire
Royal to cornflower blue
Read the Guide →Emerald
Colombian to Zambian green
Read the Guide →Aquamarine
Blue-green beryl
Read the Guide →Morganite
Pink to rose beryl
Read the Guide →Heliodor
Golden yellow beryl
Read the Guide →Alexandrite
Colour-change chrysoberyl
Read the Guide →Chrysoberyl
Cat’s eye and yellow varieties
Read the Guide →Garnet
Tsavorite to deep red pyrope
Read the Guide →Spinel
Mogok and Mahenge spinels
Read the Guide →Tourmaline
All species
Read the Guide →Tanzanite
Violetish blue to purple
Read the Guide →Peridot
Yellowish-green olivine
Read the Guide →Zircon
Natural zircon all colours
Read the Guide →Topaz
Imperial gold to sky blue
Read the Guide →Opal
Ethiopian and Australian opal
Read the Guide →Jadeite
Imperial and commercial jade
Read the Guide →Tsavorite
Chrome-bearing green grossular
Read the Guide →Other Gemstone
Fine and rare gemstones
The Gemological Basics
- Weight
- Measured in carats (ct). One carat equals 200 milligrams.
- Dimensions
- Length × width × depth in millimetres, taken at the stone's widest points.
- Shape
- The outline of a faceted stone when viewed face-up - oval, cushion, emerald cut, and more.
- Stone Type
- How the stone is cut or presented: faceted, cabochon, rough, specimen, facet grade rough, or bead.
- Clarity
- How free a stone is from visible inclusions, graded from I (Included) to VVS (Very, Very Slightly Included).
- Colour Grade
- The saturation and tone of a stone's hue, from Faint to Vivid.
- Treatment
- Any process used to enhance a stone's appearance, from heat treatment to irradiation. Full disclosure is required on every Gemplore listing.
- Origin
- The country or region a stone was mined in. Origin can materially affect value, especially for ruby, sapphire, and emerald.
- Certification
- An independent lab's written assessment of a stone's identity, and often its treatment status and origin.
Grading
Clarity Grades
- VVSVVS - Very, Very Slightly Included
- VSVS - Very Slightly Included
- SISI - Slightly Included
- II - Included
Grading
Colour Grades
- Vivid
- Intense
- Strong
- Medium
- Light
- Very Light
- Faint
Treatments We Track
Every seller must disclose treatment status at listing. Undisclosed treatment is a violation of our Seller Guidelines.
Go Deeper
Understand where your stone comes from and how to read its certificate.