Amethyst
The essence of the color purple, amethyst is beautiful enough for crown jewels yet affordable enough for class rings.
Overview
ABOUT AMETHYST
Amethyst was as expensive as ruby and emerald until the 19th Century, when Brazil’s large deposits were discovered. It was believed to prevent intoxication—amethystos means “not drunk” in ancient Greek. Today, as the most valued quartz variety, amethyst is in demand for designer pieces and mass-market jewelry alike, and its purple to pastel hues retain wide consumer appeal.
BIRTHSTONES & ANNIVERSARIES
Amethyst is the birthstone for February and the gem for the 6th and 17th wedding anniversaries.
ST. VALENTINE
The patron of romantic love wore an amethyst ring carved with the image of Cupid.
CAMILLO LEONARDI
The astrologer wrote that amethyst quickens intelligence and gets rid of evil thoughts.
164 POUNDS
Single amethyst crystals can be huge: the GIA Museum displayed a doubly terminated crystal that weighed 164 pounds.
FACTS
Mineral: Quartz
Chemistry: SiO2
Color: Purple
Refractive Index: 1.544 to 1.553
Birefringence: 0.009
Specific Gravity: 2.66
Mohs Hardness: 7
TREATMENTS
There are a number of processes used to alter the color, apparent clarity, or improve the durability of gems.
SYNTHETICS
Some gemstones have synthetic counterparts that have essentially the same chemical, physical, and optical properties, but are grown by man in a laboratory.
IMITATIONS
Any gem can be imitated—sometimes by manmade materials or by natural materials chosen by man to impersonate a particular gem.
WHY WE LOVE THIS GEMSTONE
1
Geodes
In gem localities like Brazil, amethyst sometimes forms in hollow, crystal-lined geodes so big you can stand in them.
2
Affordable
Even fine amethyst has a modest price tag. Large gems remain affordable as price per carat does not rise dramatically with larger size.
3
Ametrine
In Bolivia, amethyst and citrine occur in the same crystal. The unique gems, called ametrine, are half purple and half yellow.
QUALITY FACTORS
Assessment of the following characteristics determines amethyst’s value.
COLOR
The finest amethyst color is strong reddish purple to purple with no visible color zoning.
CLARITY
Most amethyst doesn’t have inclusions you can see without magnification.
CUT
Amethyst is cut into a variety of standard calibrated shapes, including rounds and ovals.
CARAT WEIGHT
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Amethyst is available in all size ranges for setting into a variety of jewelry styles.
Amethyst Quality Factors: The Comprehensive Guide
Research
Explore sources, gemological research, and the role of gems in history.
Ziyin Sun, Jonathan Muyal, and Dylan Hand , Aug 9, 2018
Fabrizio Troilo, Abdelghani El Harfi, Salahaddine Mouaddib, Erica Bittarello, and Emanuele Costa , Apr 30, 2015
Ziyin Sun and Jonathan Muyal , Nov 7, 2016
Recommended Reading
Amethyst Uruguay: two centuries of amethyst mining
Reinhard Balzer
Colored Gemstones: The Antoinette Matlins Buying Guide
Antoinette L. Matlins
