Mining and Classifying Turquoise

Posted: December 2, 2013 By:

02

Dec

Mining and Classifying Turquoise

Posted: December 2, 2013 By:

Although many stones are used in Native American Indian jewelry, one of the most used and recognized is turquoise. The gem, which is “a hydrous phosphate of aluminum, containing copper, iron and other minerals,” ranges in color from bright green to blue-tinted, the array of which can be found in mines dotting the American Southwest.

For centuries, turquoise mines have produced stones used in Pueblo ceremonies and jewelry. Today, many mines are closed, making turquoise harder to find and, consequently, more valuable.

How Turquoise is Mined

One reason turquoise may have been so prevalent in early Pueblo art is the relative ease with which it can be found. Turquoise deposits can be found in surface rocks and can be separated from the host rock with hand tools. Many deposits lead to larger veins that run deeper underground and/or in mountainsides.

Because the mineral composition of turquoise includes copper, turquoise is often a by-product of copper (and gold) mining. In fact, owners of open-pit copper and gold mines often make more money by selling turquoise mining rights on their property.

Major Turquoise Mines

Turquoise is found all over the world in a number of climates—from the arid Southwest and Chilean deserts to the heavily vegetated mountainsides of central China. Turquoise is usually named for the mine from which it came, and many mines produce turquoise with a characteristic appearance.

Turquoise commonly seen in pieces at Palms Trading Company include:

 

Type of Turquoise

Mine Location

Characteristic Appearance

#8

number8

Nevada

Brown- to black-matrixed light blue (some stones are darker blue, closer to the color of lapis)

Blue Gem

Blue Gem

Nevada

Green to bright blue with greenish, golden or brown matrix (usually a naturally hard stone)

Boulder or Royston Ribbon

ribbon turquoise

Nevada (Royston/Pilot Mountain mines)

Often ivory to golden brown with bright blue ribbon or vein of color

Carico Lake

carico lake

Nevada

Green stone with black or brown spider web matrix

Dry Creek

711-1.jpg

Nevada

Cream white with brown to gray/black matrix

Kingman

kingman

Arizona

Cerulean to dark blue with golden or black matrix

Montezuma

Nevada

Blue-green with dark brown mottled matrix

Morenci

845-1.jpg

Arizona

Bright blue with reddish brown matrix

Pilot Mountain

pilot mountain

Nevada

Blue to blue-green, often on the same stone, with golden brown matrix

Royston

royston

Nevada

Deep green to bright blue with light brown matrix

Sleeping Beauty

sleeping beauty

Arizona

Sky blue with little to no (light gray) matrix

 

Historically, Native American Indian jewelry may have had turquoise stones mined in New Mexico (Cerillos, Enchantment, Hachita and Santa Rita), but many mines have been closed for decades.

Turquoise Classifications

Because so many turquoise mines in the Southwest have closed in recent decades, natural turquoise has become more expensive. Imitation or highly treated stones have entered the market to provide less expensive materials for jewelry makers. However, the relative value of these stones was not always accurately reflected in prices traders offered. In the interest of consumer protection, the New Mexico Indian Arts and Crafts Act of 1973 outlined a turquoise classification system.

The classification system outlines five basic categories, which covers a number of processing methods used to prepare stones for use in jewelry.

 

Turquoise Category

Processing Methods

Description

Natural (highest value)
  • Water-based polishes
Polish does not affect color
Stabilized
  • Color stabilized
  • Polymerized or lacquered fractures
  • Oil-based polishes
  • Silicated
  • Waxed/oiled
Processing method may provide obvious color gain as it enhances shine and/or hardens or seals
Treated
  • Color shot
  • Enhanced matrix
  • Natural enhanced
  • Lacquered and dyed
  • Silicated
Processing method may significantly enhance color and/or matrix contrast as it hardens or seals
Reconstituted
  • Compressed block
Larger stone created from compressed turquoise nuggets (processing method may or may not add dye)
Block/recon (lowest value)
  • Dyed plastics
Turquoise stone made of non-turquoise materials

Palms Trading Company carries jewelry by true craftsman, jewelry artists who create unique pieces using the highest quality materials possible. If you have any questions about the type of turquoise featured in a piece, our knowledgeable staff will be happy to answer your questions.