Hetian Jade and Mutton-fat White Jade: GB Standards Definition & Grading (2020/2024 GB Summary)

Source: The following data is compiled from the 2020 and 2024 Chinese National Standards (GB) for "Classification and Grading of Hetian Jade".

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1. Definition of Hetian Jade (Nephrite)

Hetian Jade (also known as Nephrite) refers to a tremolite mineral aggregate that occurs naturally, possesses beauty, durability, rarity, and craftsmanship value, and can be processed into jewelry or ornaments.

The primary mineral is tremolite. Actinolite can be a secondary mineral. It may also contain minor amounts of minerals such as calcite, diopside, graphite, pyrite, chromite, magnetite, quartz, serpentine, chlorite, epidote, wollastonite, apatite, and garnet.

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2. Major Properties & Composition (GB Highlights)

• Refractive Index (Spot test): 1.60 – 1.61

• Density: 2.95 (+0.15 / -0.05) 

• Chemical Composition (Main Mineral): Tremolite Ca₂(Mg,Fe)₅Si₈O₂₂(OH)₂

• Crystal System: Crystalline aggregate, commonly occurring in fibrous, foliated, or scaly aggregates.

• Luster: Vitreous luster, greasy luster

• Mohs Hardness: 6 – 6.5

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3. Definitions of White Jade / Mutton-fat White Jade

White Jade

Hetian jade whose body color is predominantly white, which may carry slight tints of other hues.

Mutton-Fat Jade

White jade that simultaneously achieves Grade A across all four categories: Color, Texture, Clarity, and Uniformity.

 

4. Grading on Colors (White Jade)

Color Level	Grade	Color Characteristics
Pure White	A	Pure white color, completely free of variegated colors or color casts.
Fine White	B	Relatively pure white color, may carry an extremely slight tint of other hues.
White	C	White color, carrying a slight tint of other hues.

5. Jade Texture Grading (Hetian Jade)

Texture Level	Grade	Visual Characteristics (Naked Eye)
Fine & Delicate	A	Texture is exceptionally fine, delicate, and dense with a greasy feel. Granular structures are barely visible under transmitted light.
Moderately Delicate	B	Texture is relatively fine and dense with a moderately greasy feel. Granular structures are visible under transmitted light but barely visible under reflected light; the granular structure is relatively uniform.
Average	C	Texture is not delicate, relatively loose, and lacks a greasy feel. Granular structures are visible under reflected light; the granular structure is uneven.

6. Clarity and Inclusions Grading

Clarity Level	Grade	Visual Characteristics (Naked Eye)
Pure	A	Only a few tiny pinpoints, minor cotton flecks, or water lines are visible. These clarity features have little to no impact on the overall aesthetic value.
Moderately Pure	B	Noticeable pinpoints, cotton flecks, water lines, or minor fractures are visible, which have a certain impact on the overall aesthetic value.
Average	C	Obvious and numerous pinpoints, cotton flecks, water lines, inclusion minerals, or fractures are highly visible, significantly impacting the overall aesthetics and/or durability.

7. Uniformity Grading

Uniformity Level	Grade	Visual Characteristics (Naked Eye)
Uniform	A	The overall color and texture are consistent and uniform; or the non-uniform portion accounts for no more than 5% of the total and does not affect the overall aesthetics.
Moderately Uniform	B	The primary color and/or texture are uniform. The local non-uniform portion accounts for more than 5% but less than 20% of the total, having a minor impact on the overall aesthetics and quality.
Average	C	The color and/or texture are distinctly uneven. The non-uniform portion exceeds 20% of the total, significantly affecting the overall aesthetics and quality.