How to identify Chrysoprase

To correctly identify Chrysoprase (SiO2 (with nickel inclusions)), 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

   Apple-green to yellowish-green, sometimes with brownish or whitish streaks. The color is typically uniform but can show banding.

2. 2

   Luster

   How the surface reflects light: metallic, vitreous, dull

   Waxy to dull, sometimes vitreous on freshly broken surfaces.

3. 3

   Texture

   Grain size and surface feel: coarse, fine, glassy

   Microcrystalline, dense, and fine-grained. Often exhibits a conchoidal fracture.

4. 4

   Crystal Form

   Shape of visible crystals or crystal faces

   Cryptocrystalline, meaning individual crystals are too small to be seen without high magnification. Typically occurs in massive, botryoidal, reniform, or stalactitic habits.

5. 5

   Cleavage

   How it breaks: flat cleavage planes vs irregular fracture

   None, due to its cryptocrystalline nature.

6. 6

   Geological Environment

   The rock formation and setting where it occurs

   Found in weathered zones of nickel-rich ultramafic rocks (e.g., serpentinites, dunites) and lateritic nickel deposits. It often occurs in association with goethite, magnesite, and other secondary minerals.

Key Facts

Hardness

7 (Mohs scale)

Specific Gravity

2.58 - 2.64

Crystal System

Trigonal (cryptocrystalline aggregates)

Color

Apple-green, yellowish-green

Luster

Waxy to dull, sometimes vitreous

Transparency

Translucent to opaque

Fracture

Conchoidal to uneven

Cleavage

None

Composition

Silicon dioxide (SiO2) with trace nickel inclusions

Physical characteristics

• Crystal Habit: Cryptocrystalline, massive, botryoidal, reniform, stalactitic
• Cleavage Type: None
• Fracture Type: Conchoidal to uneven
• Tenacity: Brittle
• Luster Type: Waxy to dull, sometimes vitreous

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