Typical Gem Identification Problems

This guide lists some gems that the author has found are commonly confused with cheaper varieties in TV jewelry stores and auction sites. The imitations are shown in parenthesis.   The GIA Gem Identification Lab Manual lists other confusions. Many lab gems are confused with cheaper lab gems. Most mistakes are innocent. Expensive gems should be tested.

We use standard GIA color abbreviations: c=colorless, V=violet, B=blue, G=green, Y=yellow, O=Orange, R=red, P=purple, OR=orange red, Bl=black, W=while, Gr=gray, Br=Brown, Pk=pink).

COLORLESS

•   Danburite (c Topaz)
•   Beryl (c Quartz)
•   Hambergite (c Quartz)
•   Lab Diamond (CZ, Glass, Quartz, Yag, GGG, Strontium Titanate, Lab Rutile).
•   Lab Moissanite (Lab spinel)
•   Colorless Corundum - Sapphire (lab spinel, lab c corundum)

BLUE & VIOLET

•  V Sapphire (V spinel, iolite)
•  Tanzanite (glass, CZ, lab corundum)
•  *Lab Forsterite (glass)
•  *Lab Kyanite (lab quartz)
•  *Lab Tourmaline (lab spinel)
•  *Lab Topaz (lab spinel)
•  *Lab Aquamarine (lab spinel)

* There is virtually no lab kyanite, lab tourmaline, or lab topaz in the jewelry market.  Lab Forsterite and lab Aquamarine are expensive ($25-50 / carat).  Lab Quartz, Lab Flame Fusion Spinel & Corundum, CZ, glass, and plastic are inexpensive (often under $0.50 / ct).

COLOR CHANGE

•   G/R Lab Alexandrite-Chrysoberyl (B/P Lab Corundum, glass)

Czochralski chrysoberyl is expensive (about $25-50 per carat).  Flux synthetics --  chrsyoberyl, spinel and corundum are also expensive  (about $120 per carat).  Synthetic diamonds are extremely expensive.

GREEN

• Tsavorite Grossular Garnet (G glass, CZ)
• Chrome Diopside (G tourmaline, G lab quartz)
• Emerald and Lab Emerald (glass, CZ, G Yag)
• Demantoid Garnet (Mali Garnet)
• Enstatite (G Tourmaline)
• Green Zircon (G tourmaline)
• Green Topaz (G Tourmaline, glass, CZ)
• Peridot (glass, CZ)
• Kornerupine (G Zircon)

BROWN, ORANGE , YELLOW

• Br Axinite (Quartz)
• Br Topaz (Quartz)
• Br Enstatite (Tourmaline)
• Br Andalusite (Tourmaline)
• O Bustamite (Carnelian)
• O Malaia Garnet (Topaz)
• O Hessonite Grossular Garnet (Almandite Garnet)
• O Spessartite Garnet (O Tourmaline)
• OR Spessartite Garnet (Almandite Garnet)
• Y Aragonite (Calcite)
• Y Chrysoberyl (CZ, Zircon)
• Y Imperial topaz (common coated Topaz, Quartz)
• Y Brazilianite (chrysoberyl)
• Y Mali Garnet (Y CZ)
• Y Montebrazite & Amblygonite (Calcite)
• Y Spodumene (Y coated topaz)

RED

•  R Spinel (Rhodolite Garnet)
•  R Labradorite or Andesine Feldspar (R CZ)
• R Tourmaline (Almandite Garnet)

OPAQUE GEMS

• Y Serpentine (Y Chalcedony)
• G Jadeite (Nephrite, Aventurine Quartz, Serpentine)
• Thomsonite (Chalcedony)
• Pearls (W glass)
• Bl Jet (Bl plastic, Bl glass)
• B Sodalite (B Aventurine Quartz)
• R Horn Coral (Chalcedony)

In another guide the author will list tests that can be done with relatively inexpensive equipment.

Taaffeite, Ph.D. Graduate Gemologist (GIA)