Color grading chart of Jade

Imperial Jade is vivid green jadeite and it is the most valuable.

The jade and nephrite are equally beautiful in their texture, toughness and colour of pastels to strong earthy colour and the most well known green.

They are commonly used and appreciated in jewellery.

Some individuals used to be in love with it to the extent of being obsessed with it in the past. The jade has been a significant feature in the history of the world in the sense that this obsession has resulted in war like the ancient Chinese emperor Qianlong who was obsessed with the jade to the extent of invading ancient Burma to find its deposits.

The Qin Dynasty sculptures, objects, and jewellery held by the emperor are regarded as one of the largest and the most valuable collections in the globe.

Colar de jade Hutton Mdivani

The price of jade stimulated the digging in of imperial treasures by the French, British and Japanese, by the adventurers and the bandits. It also fascinated the rich and the famous who started to hoard the gem, all of which contributed towards causing a rise in its price.

And all these tales led to the birth of the book, a concept of two journalists Adrian Levy and Cathy Scott-Clark, who undertook a huge work to bring out the interesting history of this treasure of a book.

Pedra Jade - Características, Variedades e História.

Jade

Gemological Characteristics

• jadeite

• Crystal form: monoclinic, intergrown masses of fine granules.

• Chemical formula: NaAlSi 2 O6

• Hardness: 6 1/2 to 7 Mohs

• Density: 3.30 - 3.38

• Transparency: opaque, transparent.

• Colour: Green, yellow, white, reddish, lavender, grey and black.

• Lustre: greasy to pearly.

• Fluorescence: pale green, greyish blue.

• Fracture: friable.

• Refractive index: 1.652 - 1.688.

The jadeite has the typical spectral of absorption in the visible light range that can be viewed on the edges of the more opaque gems.

It possesses shine on fractured surfaces, and a greasy shine on polished surfaces.

Nephrite

Crystal system: monoclinic, tangled masses of fine filaments.

• Formula: Ca2 (Mg, Fe)5 (Si 4 O11)2 (OH) 2.

• Hardness: 6 to 6 /12 mohs

• Density: 2.90 - 3.03

• Transparency: Opaque.

• Colour: Green, yellow, white, reddish, grey and brown. Often mottled.

• Lustre: greasy to pearly.

• Fluorescence: none.

• Fracture: fragile, cracked.

• Refractive index: 1.600 - 1.627.

Nephrite is an Iberian form of the actinolite-tremolite sequence of minerals and hence its structure is more powerful as compared to jadeite.

Mottled and banded are the prevailing colours of most of the specimens, but specimens with homogeneous colours are also possible.

Types of nephrite and jadeite

Pure jadeite is white. We have already noted that both jadeite and nephrite can change in colour through the existence of certain impurities, which are iron and manganese.

The colours are pastel and opaque, except Imperial Jade, which is special lustre and is either translucent or semi-translucent. Jadeites which are of homogenous colours are more highly rated.

Emerald green, spinach green and apple green are regarded as very useful in the West.

Pure white and yellow on a light pink background is much here in the Far East.

Imperial  jade

This is a jadeite that is located in Burma, Myanmar. Its coloured emerald green is translucent down to transparent.

Jade Imperial

This is the dearest and most desired type, 

It has a bright colour because of the inclusion of chrome. Black inclusions may be small on a specimen.

They are not big but are perfect.

Yunan Jade

This is the Chinese name of jadeite, which was a name of the Chinese province where jade was imported out of Burma.

These are inferior jadeites in comparison to imperial jade.

They occur in secondary deposits in conglomerates or pebbles found in the north of Burma. They also occur in layers that have interspersed serpentine.

Grey Jade

Nephrite is commonly referred to as merely jade.

Its colours are also less delicate and pure as that of jadeite. They include dark green (which includes iron oxide), and pastel (magnesium-rich) colours.

They may be mottled, banded or homogeneous.

The colour of nephrite is normally spinach or sage green.

Jade Amarela

Black is very dark green. When the nephrite fibres are parallel, a chatoyance effect (cat's eye effect, sparkle) could be obtained which could not be done with jadeite because it is granular.

Coloured Jades

Yellow Jade

Albite Jade - This is of two kinds. One is a blend of jadeite and albite, green containing black dots and has its origin in Burma. The other one is a chloromelanite. It is made up of kosmoklor, a material that is similar to jadeite mixed with albite, jadeite and other minerals. It is a deep green colour, dark green with dark green veins and flecks due to the presence of chlorite. It is also found in Burma.

• Nephrite Jade

• Red JadeJade Cinza

• GreyJade

• White Jade

• Black Jade

• Colour and dyeing

Jade is often treated. It may be blotted with acid so as to take away pigment or stain.

This exposes the gem to more porousness and can easily fracture, thus the fractures are normally filled in with a polymer to enhance their looks.

Such treatment, or even a colouring, may be checked by means of a piece of equipment known as a Chelsea screen (a screen evolved to tell genuine emeralds and fakes, but also frequently applied to other gems).

Red Jade

Despite the processing of a large amount of jade, finding natural jade is not too hard.

Grading

The Chinese jade industry has a system of grading and the jade is graded depending on how much has been done to the jade.

This is a jade grading system, which is described through grades -: A to D:

Grade A - the jadeite has neither been filled nor coloured, but could be coated and is thought to be stable.

Grade B - can be filled and bleached, without being coloured.

Grade C - dyed and filled.

Pedra de Jade lapidada

Cut  Jade Stone

Grade D - not natural jade.

Cutting and Usage

Jade is highly flexible and may be cut as well as cut and carved into fine art forms.

It is carved into a variety of traditional Chinese figures such as Buddhas, dogs, dragons, bats and butterflies, but also into rounded, geometric shapes, in short, it has many possibilities that vary according to the design of the piece that will use it.