Jadeite: The mineral Jadeite information and pictures

About

Jadeite is most famous for its gem form of Jade. Jewelry and ornamental carvings were made from Jade throughout history. Jade was very precious in some ancient societies, and was sometimes worth even more than Gold. Jadeite is not the only form of Jade; the amphibole mineral Nephrite (a variety of Actinolite) also has a gem form of Jade.

On a gemological standpoint, all tough masses of Jadeite and Nephrite are called Jade. The Jadeite and Nephrite forms of Jade are almost identical, and it may be very difficult to distinguish the two. In fact, they were thought to be one mineral type until 1863, when it was discovered that they are scientifically different minerals. Jadeite Jade is the rarer and more valuable form of Jade. The most common color for both forms of Jade is pale green. Emerald-green Jade, known as Imperial Jade, is the most valuable form of Jade.

Jadeite is rarely represented in mineral collections, since it is usually uninteresting in its rough form and commercially mined only for gemstone use.

Identification

Chemical Formula: NaAlSi₂O₆
Composition: Sodium aluminum silicate, sometimes with some calcium and iron
Color: Light to dark green, apple-green, emerald-green, gray, white, and cream-yellow. Often mottled white and light green. Occasionally also yellow, pink, purple, brown, and black; sometimes multicolored or banded.
Streak: White
Hardness: 6.5–7
Crystal System: Monoclinic
Luster: Waxy, greasy; pearly on cleavage surfaces. Polished material may be vitreous.
Cleavage: 1,2 - prismatic at cleavage angles of 87º and 93º (Characteristic of minerals in the pyroxene group). Due to its lack of crystals, cleavage is rarely observed.
Fracture: Splintery, uneven
Tenacity: Brittle
Transparency: Translucent to opaque
Specific Gravity: 3.3–3.5
Group: Silicates; Inosilicates; Pyroxene Group
Rock Type: Metamorphic

Rankings

Popularity (1–4): 1
Prevalence (1–3): 2
Demand (1–3): 1

Crystal Forms & Aggregates

Visible crystals are very rare. Most often as tough masses of dense fibers and interlocking blades. These masses may be smooth and waterworn, or they may be rough and massive. When crystals do occur, they are small, slender, and in bladed aggregates.

Striking Features

Color, crystal habits, and mineral associations

Environment

In metamorphosed Serpentine deposits rich in sodium, in hydrothermal replacement deposits, and in placer deposits.

Varieties

✓ common · ✗ uncommon

Jade— Gem form of Jadeite faceted or carved for ornamental or gemstone use.
For more information, see the gemstone Jade.

Uses

Jadeite is an important mineral, as it is the primary form of the gemstone Jade. It is cut into cabochons, beads, and earrings, and some rings and bracelets may be carved out of an entire mass of Jade. Valuable ornamental sculptures and figures are often carved from this gem.

See the gemstone section on Jade for more information.

Noteworthy Localities

Some of the finest Jadeite comes from Tawmaw, Myanmar (Burma), which is one of the largest producers of gem-quality Jade. Other important deposits are Itmurundy Massif, Krasnyi Oktyabr, Kazakhstan; Kharp, Siberia, Russia; Yunian, Tibet, China; Itoigawa, Niigata Prefecture, Japan; and Sierra de las Minas, Motagua Valley, Guatemala.

In the U.S., large masses come from Clear Creek in the Diablo Range, San Benito Co., California; and waterworn nuggets from Cape San Martin (Jade Cove), Big Sur, Monterey Co., California. Small yet visible crystals come from the Russian River in the vicinity of Cloverdale, Mendocino Co., (and nearby Sonoma Co.) California.

Common Mineral Associations

Serpentine, Nepheline, Calcite, Quartz, Aragonite, Glaucophane, Vesuvianite

Distinguishing Similar Minerals

Nephrite - Has a lower specific gravity than Jadeite, otherwise very difficult to distinguish.
Serpentine - Softer, less dense, has a greasy feel.