JADE

 JADE

  Jade (from Mandarin Chinese: "yu" or "yǔ") means beautiful and durable. In English, it is pronounced "jade." Generally, the term refers to a semi-translucent to nearly opaque green stone that goes by various names, such as Burmese jade, Chinese jade, Indian jade, and moss-in-snow jade.

In gemology, jade refers to stones composed primarily of either jadeite or nephrite. If jadeite is the dominant mineral, it is called jadeite jade; if nephrite is dominant, it is known as nephrite jade. Among the two, jadeite jade is rarer and more valuable than nephrite jade. In the gemstone market, both types are considered genuine jade. Interestingly, the name "jadeite" is derived from the word "jade" itself.

Jade is classified as a rock, not a single crystal, because it consists of densely packed microscopic mineral crystalsa structure known as cryptocrystalline. Under a microscope, jadeite jade shows a granular texture, while nephrite jade has a tightly interwoven fibrous structure. This fibrous texture makes nephrite tougher than jadeite. In fact, jade is harder than most rocks and tougher than steel. Although it is not transparent like many faceted gemstones, jade is exceptionally tough and resistant to breakage, unlike more brittle transparent crystals.

Jadeite Jade
Jadeite jade is a type of jade that is more translucent than nephrite jade and is found in only a few locations worldwide. It is considered the most valuable form of jade. High-quality jadeite jade primarily comes from Myanmar, which is why it is often referred to in the trade as Burmese jade.

Mineral Family
Jadeite belongs to the pyroxene group of minerals and has the chemical formula NaAlSiO. It crystallizes in the monoclinic system, though it rarely forms large single crystals. Instead, it typically occurs as a dense aggregate of fine-grained crystals.

Sources
The most significant source of jadeite jade is Myanmar. Other sources include Guatemala, Japan, and the United States, though the jadeite from these locations is generally of lower quality.


General Properties

• Hardness: 6.57 on the Mohs scale
  
• Refractive index: 1.66
  
• Specific gravity: 3.3
  
  Distinctive Characteristics
  Jadeite jade is known for its greater translucency and broader color range compared to nephrite jade. Its colors include green, lavender, brown, yellow, and more. The coloring comes from trace elements within the mineral structure:
  
  
• Chromium: produces green hues
  
• Iron: causes yellow, brown, or orange tones
  
• Manganese: gives pink to purplish-brown shades

High-quality jade should possess three main natural qualities, known as the 3Ts:

1. Tone the intensity and uniformity of the color throughout the stone.
   
2. Transparency the degree to which light passes through the jade, indicating its translucency.
   
3. Texture the smoothness and fineness of the jade's surface and internal structure.
   

Additionally, it is important to verify whether the jade has undergone any treatment or enhancement, as treated jade typically commands a lower price compared to untreated, natural jade.

  Beliefs
The Chinese regard jade as a treasured family heirloom. Jade has long been popular as both jewelry and as a protective amulet.


Care and Maintenance
Avoid exposing jade to high heat or open flames, as it can melt. Also, keep it away from acids and chemicals, which may cause mild reactions and damage the stone.


Quality Enhancement Methods
There are three common methods used to improve the color and clarity of jade:

1. Dyeing: Before dyeing, jade is often surface-etched or heat-treated to help the dye penetrate deeper into the stone.
   
2. Filling with colorless substances: Paraffin is commonly used to fill cracks, making the jade appear clearer and smoother.
   
3. Heating: Jade with yellow or brown impurities may be heat-treated to change its color to brown or reddish-brown.
   
   Grading in the Jade Trade
   In the jade market, jade is generally classified into three grades based on its texture and quality:
   
   (If you want, I can help translate the details of these three grades too.)

  Jade Grades

Grade A Jade
Grade A jade is completely natural and untreated, except for a surface wax coating. The color is natural without any dyeing or bleaching. This type of jade is considered high quality and commands a high price.


Grade B Jade
Grade B jade has been chemically bleached using acids or organic acids to remove impurities or unwanted colors. This process makes the jade appear more translucent and bright green. After bleaching, the jade is coated with wax. Under high magnification (30x or more), the surface shows a crackled pattern caused by the acid etching.


Grade C Jade
Grade C jade is dyed to imitate high-quality jade. It is considered low quality. Under high magnification (30x or more), green color concentrates especially along cracks. A simple test involves wrapping the jade in a damp cotton ball for 23 days; if green stains the cotton, the jade has been dyed. Before testing, any wax coating should be removed by wiping with cotton soaked in oil or warm water. Boiling the jade in hot water or acid will cause most of the dye to wash out.


Grade B + C Jade
This jade has undergone both dyeing and bleaching. After dyeing, it is lightly bleached to improve clarity and achieve a bright green color similar to Grade A jade. Detecting this type of jade is difficult because dye concentrations along cracks are removed. If natural dyes are used, their reaction with jade complicates detection further. Dyed jade colors gradually shift to brownish-yellow over time, causing the surface to darken.


Synthetics
No synthetic jade has been found to date.


Imitation and Comparable Gemstones
Several stones can resemble jade, including:

• Aventurine quartz
  
• Chrysoprase
  
• Dyed green quartzite
  
• Green grossular garnet
  
• Serpentine
  
• Dyed marble
  
• Green-colored plastic and glass
  
• Maw-sit-sit
  
• Saussurite

Inspection / Identification

Aventurine Quartz is actually a type of rock composed of tightly packed quartz grains, known as quartzite. The term "aventurine" refers to its sparkling or glittering appearance. Generally, quartzite is white in tone, but it appears green when it contains scattered flakes of the mineral fuchsite mica.

Aventurine quartz closely resembles nephrite jade, and it is sometimes even called Indian jade.

Dyed Quartzite
As mentioned earlier, quartzite is a rock that is naturally white and somewhat translucent. To imitate high-quality jade, quartzite is often infused with green resin. The resin seeps into cracks or spaces between quartz grains, giving the stone a vivid green color and a translucent appearance similar to fine Burmese jade.

The green resin is water-resistant, but over time, the color may gradually shift to a brownish-green. This happens because the resin deteriorates and turns yellow, which mixes with the green to create a brownish hue.

A simple way to identify this treatment is to look for very intense green color concentrated along cracks or quartz grains. This effect becomes especially noticeable when light shines through the stone.

    Chrysoprase
Chrysoprase is a mineral in the chalcedony group, which belongs to the microcrystalline quartz family. It is mostly apple green to yellowish-green or green mixed with brown. The green color comes from nickel ions incorporated within the mineral crystals. Sometimes it is called Maw Sit Sit jade. Chrysoprase is especially popular in Japan due to its smooth, consistent green color and hardness, which is greater than that of both jadeite and nephrite jade. Australia is known for producing high-quality chrysoprase, hence it is sometimes called Australian jade.


Green Grossular Garnet
Green grossular is a variety of garnet that comes in many colors, including green shades similar to jade. It is sometimes known as Transvaal jade. This type of jade often contains black inclusions. To distinguish grossular jade from nephrite and jadeite, observe the weight and refractive indexgrossular is noticeably heavier and has a higher refractive index than both jadeite and nephrite.


Glass and Plastic Imitations
There are many glass and plastic imitations of natural jade on the market, but they can be clearly distinguished from genuine jade. Plastic jade feels unusually light and often contains many air bubbles, sometimes showing green spots. Another imitation is made from melted glass with green coloring, which looks more like natural jade but still contains bubbles visible under magnification.

Another way to identify glass or plastic jade is by touchthese imitations usually feel warmer than genuine jade. Genuine jade is composed of tightly packed mineral crystals that conduct heat better than amorphous (non-crystalline) glass or plastic, so real jade feels cooler to the touch.

Nephrite jade

Nephrite Jade
Nephrite jade typically has a more opaque texture and darker colors compared to jadeite jade. It has been known and valued alongside jadeite for a long time. Nephrite comes from various sources and is known by several other names, such as Taiwan jade, New Zealand jade, and New Zealand greenstone. Nephrite jade is often carved into Buddha statues and deities, such as the Emerald Buddha, which is a highly revered sacred object in Thailand and considered a national treasure. It is believed to be made from high-quality nephrite jade with a rich green color similar to emerald.


Mineral Family
Nephrite belongs to the amphibole mineral group, composed mainly of actinolite-tremolite minerals with the chemical formula Ca2(Mg,Fe)5Si8O22(OH)2. Its crystal structure is monoclinic, similar to that of jadeite.


Sources
Important sources of nephrite jade include Taiwan, Canada, Australia, and New Zealand. Other notable locations are China, the United States, and Russia.


General Properties

• Hardness: 5 to 6 on the Mohs scale
  
• Refractive index: 1.61
  
• Specific gravity: 2.9 to 3.1

Distinctive Characteristics
Nephrite jade is tougher than jadeite because it consists of tightly interwoven needle-like or fibrous crystals. It is more opaque and has a luster similar to oily or waxed surfaces. Its colors are generally limited to white, green, brown, and gray. Small black spots of iron oxide inclusions are often scattered throughout the stone.


Popular Shapes and Uses
Due to its toughness, nephrite jade is favored for intricate carvings such as statues of Chinese deities or thin-walled vases. It is also used to make jewelry like rings, bracelets, and beads, as well as utilitarian items like cups, bowls, plates, and seals for nobility.

  Popularity in the Gem World
Nephrite jade is almost as popular as jadeite jade worldwide. Generally, nephrite jade is somewhat less expensive than jadeite, likely because it is more abundant and tends to have a more opaque texture.


Beliefs
The Chinese have used nephrite jade for a long time. Nephrite jade bracelets are common, and nephrite is also known as Taiwan jade. The Chinese regard jade as a family heirloom. Jade is popular for use in jewelry and amulets because its green color evokes a calming and cooling feeling.


Care and Maintenance
Avoid exposing nephrite jade to high heat flames or acidic chemicals.


Quality Enhancement
Compared to jadeite, nephrite jade is less commonly treated. The main purposes of enhancement are to lighten its green color or reduce black spots. The three common treatments are:

Dyeing with lighter colors
Impregnating with paraffin wax
Heat treatment (firing)

Synthetic Jade
No synthetic nephrite jade has been found to date.


Comparable Gemstones

• Serpentine
  
• Maw-sit-sit
  
• Malachite

In the market, serpentine jade is more commonly found than Burmese jade or Taiwan jade because serpentine jade is cheaper and easier to carve.

Maw-sit-sit is a rock composed of several minerals, such as ureyite, amphibole, chlorite, feldspar, and other minerals. The proportions of these minerals vary, resulting in a range of green tones. Most maw-sit-sit stones are dark green and opaque, resembling malachite, but often contain black spots or black streaks scattered throughout the stone. The main source of maw-sit-sit is Myanmar (Burma).

Malachite is an opaque dark green stone with striking bands or stripes. It mainly consists of copper carbonate and water, which gives it a cool sensation when touched. Because of this, malachite is often used to make bracelets, beads, necklaces, and wristbands. It is believed to help heal arthritis and reduce symptoms of fever poisoning.

Malachite has a hardness of only 3.5 to 4 on the Mohs scale, so it is vulnerable to scratches. It should be kept away from chemicals, especially acids, as these can corrode the malachite.