How to identify Jade

To correctly identify Jade (Jade), check each of these features in order. Many rocks and minerals look alike, so cross-reference multiple properties before deciding.

Step-by-step identification

1. 1

   Color

   Overall color and any zoning or banding

   Jadeite: Typically ranges from white, green (emerald green, apple green, spinach green), lavender, yellow, orange, brown, black. The most prized is 'Imperial Jade' (emerald green). Nephrite: Ranges from creamy white, light to dark green, gray, brown, black. Often has a more muted, spinach-like green.

2. 2

   Luster

   How the surface reflects light: metallic, vitreous, dull

   Vitreous to greasy, often waxy when polished.

3. 3

   Texture

   Grain size and surface feel: coarse, fine, glassy

   Both jadeite and nephrite exhibit a fine-grained, interlocking fibrous or granular texture, contributing to their exceptional toughness. When polished, they feel smooth and cool to the touch.

4. 4

   Crystal Form

   Shape of visible crystals or crystal faces

   Jadeite: Monoclinic, typically occurs as granular aggregates or compact masses. Individual crystals are rarely macroscopic. Nephrite: Monoclinic, forms as dense, felted aggregates of microscopic, interlocking fibrous crystals.

5. 5

   Cleavage

   How it breaks: flat cleavage planes vs irregular fracture

   Jadeite: Two distinct cleavages at approximately 87° and 93°, but rarely observed due to its massive habit. Nephrite: Two distinct cleavages at approximately 56° and 124°, also rarely observed due to its fibrous, interlocking nature.

6. 6

   Geological Environment

   The rock formation and setting where it occurs

   Jadeite: Formed in high-pressure, low-temperature metamorphic environments, specifically in subduction zones associated with serpentinized peridotites. Nephrite: Formed by regional metamorphism of ultramafic rocks (serpentinites) or dolomitic limestones, often found in contact metamorphic zones or associated with ophiolite sequences.

Key Facts

Hardness

Jadeite: 6.5-7 on Mohs scale. Nephrite: 6-6.5 on Mohs scale. (Note: While jadeite is slightly harder, nephrite's interlocking fibrous structure makes it exceptionally tough, sometimes even tougher than jadeite in terms of resistance to breaking.)

Specific Gravity

Jadeite: 3.30-3.38 g/cm³. Nephrite: 2.90-3.03 g/cm³.

Crystal System

Monoclinic for both Jadeite and Nephrite.

Color

Wide range, predominantly green (emerald, apple, spinach), white, lavender, yellow, orange, brown, black.

Luster

Vitreous to greasy, often waxy when polished.

Transparency

Translucent to opaque, rarely semi-transparent.

Fracture

Splintery (nephrite) to granular (jadeite), very tough.

Cleavage

Jadeite: Good in two directions at ~90°. Nephrite: Good in two directions at ~60°/120°. Cleavage is rarely observed due to the massive, interlocking nature of both minerals.

Composition

Jadeite: Sodium aluminum silicate (NaAlSi₂O₆). Nephrite: Calcium magnesium iron silicate (Ca₂(Mg,Fe)₅Si₈O₂₂(OH)₂).

Physical characteristics

• Crystal Habit: Jadeite: Granular to compact massive aggregates. Nephrite: Dense, felted, interlocking fibrous aggregates.
• Cleavage Type: Jadeite: Prismatic {110} at ~87° and 93°. Nephrite: Prismatic {110} at ~56° and 124°. Both are rarely observed due to the fine-grained, massive nature.
• Fracture Type: Splintery (nephrite) to granular (jadeite), conchoidal in some compact varieties.
• Tenacity: Extremely tough (resistance to breaking, chipping, or cracking), making it ideal for carving.
• Luster Type: Vitreous to greasy, often waxy on polished surfaces.

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