How to identify Jadeite

To correctly identify Jadeite (Jadeite (NaAlSi2O6)), 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

   Highly variable, including white, various shades of green (from pale to emerald green, often mottled), lavender, blue, black, brown, and orange. The most prized color is an intense, translucent emerald green, known as 'Imperial Jade'.

2. 2

   Luster

   How the surface reflects light: metallic, vitreous, dull

   Vitreous to greasy, sometimes pearly on cleavage surfaces.

3. 3

   Texture

   Grain size and surface feel: coarse, fine, glassy

   Typically fine-grained, compact, and interlocking fibrous or granular, contributing to its exceptional toughness. Can appear massive.

4. 4

   Crystal Form

   Shape of visible crystals or crystal faces

   Rarely forms distinct crystals; usually found as massive, granular, or fibrous aggregates. When crystals are present, they are typically prismatic with a square or rectangular cross-section.

5. 5

   Cleavage

   How it breaks: flat cleavage planes vs irregular fracture

   Perfect prismatic cleavage in two directions at approximately 87 and 93 degrees, characteristic of pyroxenes. However, due to its interlocking fibrous nature, cleavage is rarely observed in hand specimens and it tends to fracture conchoidally or unevenly.

6. 6

   Geological Environment

   The rock formation and setting where it occurs

   Found in high-pressure, low-temperature metamorphic rocks, specifically blueschist and eclogite facies. It occurs in serpentinite-associated metasomatic rocks, often in veins or lenses within serpentinite bodies, or as part of metamorphic rock assemblages in subduction zones.

Key Facts

Hardness

6.5-7 on Mohs scale

Specific Gravity

3.30-3.38

Crystal System

Monoclinic

Color

White, green (various shades), lavender, blue, black, brown, orange

Luster

Vitreous to greasy

Transparency

Translucent to opaque, rarely semi-transparent

Fracture

Splintery to uneven, sometimes conchoidal due to its toughness

Cleavage

Perfect prismatic on {110} at 87 and 93, but rarely observed in massive forms

Composition

Sodium aluminum silicate

Physical characteristics

• Crystal Habit: Typically massive, granular, or fibrous aggregates; rarely as distinct prismatic crystals.
• Cleavage Type: Perfect prismatic {110} at nearly 90 degrees (87 and 93), but rarely seen due to aggregate nature.
• Fracture Type: Splintery to uneven, occasionally conchoidal.
• Tenacity: Extremely tough (resistant to breaking and chipping).
• Luster Type: Vitreous to greasy.

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