Global Gemology - Rare Gems & Jewels
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QUARTZ

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Fine amethyst and diamond ring.
Rich purple amethyst & diamond ring
Species:  Quartz
​​Mohs Hardness:  7 out of 10
Color:  Occurs in many different colors.  Scroll below for a list of the different varieties of quartz.
RI:  1.544 to 1.553 (very constant)
Birefringence:  0.009
SR/DR/AGG:  DR
Clarity Type:  Type II
Optic Character:  Uniaxial positive.  Might show a bull's eye or Airy's spiral optic figure under crossed polarizing filters.
Pleochroism:  Weak to moderate, colors vary depending on variety of quartz.
Spectrum:  Not diagnostic
Fluorescence:  Generally inert
SG:  2.66 (+0.03/-0.02)
Routine Treatments:  Varies
Additional Enhancements:  Heating, irradiation, dyeing, impregnation

Quartz Facts

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There are many different varieties of quartz, occurring in various colors.

Quartz crystals are used in electronics due to their ability to conduct electricity under pressure.

Quartz crystals allowed for battery operated watches, dating back to late 1969.

Quartz Varieties

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AMETHYST
Top quality amethyst set in a 14K white gold and diamond setting

​Amethyst is the purple variety of quartz.​
AMETRINE
Emerald cut ametrine (half amethyst, half citrine)

Amethyst and citrine are the purple and orange varieties of quartz.

Ametrine is when quartz displays the colors of amethyst and citrine in a single gem.

AVENTURINE
Aventurine quartz

Aventurine quartz is green due to many tiny, included green fuschite platelets.​  ​Aventurine has a glitter effect caused by light reflecting off the fuschite platelets.
CITRINE
Retro Era vintage 14K rose gold, platinum, 14.48 ct Madeira citrine & diamond ring

​Citrine is the yellow to orange variety of quartz.​
DENDRITIC QUARTZ
Tree branch-like inclusions inside a dendritic quartz

​Rock crystal with dendritic inclusions that resemble tree branches.
GOLD BEARING QUARTZ
Tourmalinated quartz

Gold bearing quartz contains veins of pure gold.
PRASIOLITE
Prasiolite & diamond ring set in sterling silver, by David Yurman

​Prasiolite is the green variety of quartz and is sometimes referred to as "green amethyst" or "lime citrine".
ROCK CRYSTAL
Rock crystal, aka clear quartz crystal
Photo courtesy of Mineral Miner's

​Rock crystal, also known as clear quartz, is the colorless variety of quartz.
ROSE QUARTZ
Polished rose quartz heart pendant

​Rose quartz is the pink variety of quartz.
RUTILATED QUARTZ
Photomicrograph of intersecting rutile needles inside a rutilated quartz

Rutilated quartz is rock crystal quartz included with rods of rutile.
SMOKY QUARTZ
Smoky quartz bracelet in sterling silver and yellow gold, by designer, John Hardy

Smoky quartz is the brown variety of quartz.
TIGER'S EYE
Fibrous structure in tiger's eye quartz

Tiger's eye quartz is a golden to red-brown color, with a phenomena known as "chatoyancy".
TOURMALINATED QUARTZ
Tourmalinated quartz

Tourmalinated quartz is rock crystal quartz with included tourmaline rods.

All photos courtesy of Scott Papper, GIA GG, AJP, CMA (NAJA)

  • HOME
  • ABOUT
  • SHOP
  • SERVICES
    • APPRAISALS
    • EXPERT WITNESS TESTIMONY
    • SELL YOUR JEWELRY
  • GEMOLOGY
    • GEM ENCYCLOPEDIA
    • THE ART OF GEMOLOGY
  • JEWELRY EDUCATION
    • DIAMOND FACTS
    • JEWELER DIRECTORY
    • JEWELRY PERIODS
    • POCKET WATCHES
    • NATIVE AMERICAN JEWELRY
  • GLOSSARY