How to identify Chrysoprase

To correctly identify Chrysoprase (Chalcedony (cryptocrystalline quartz) variety), 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 deep green, often uniform but can show slight banding or variations in intensity.

2. 2

   Luster

   How the surface reflects light: metallic, vitreous, dull

   Waxy to vitreous, sometimes dull on unpolished surfaces.

3. 3

   Texture

   Grain size and surface feel: coarse, fine, glassy

   Smooth, microcrystalline, often conchoidal fracture surfaces.

4. 4

   Crystal Form

   Shape of visible crystals or crystal faces

   Cryptocrystalline aggregates; individual crystals are microscopic and not visible to the naked eye. Typically massive, botryoidal, or stalactitic forms.

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

   Secondary mineral in weathered nickel-laterite deposits, often found in veins and nodules within serpentinites or other ultramafic rocks.

Key Facts

Hardness

6.5-7 on the Mohs scale

Specific Gravity

2.58-2.64

Crystal System

Trigonal (cryptocrystalline aggregates)

Color

Apple-green to deep green

Luster

Waxy to vitreous

Transparency

Translucent to opaque

Fracture

Conchoidal to uneven

Cleavage

None

Composition

Silicon dioxide (SiO2) with trace nickel (Ni2+)

Physical characteristics

• Crystal Habit: Massive, botryoidal, stalactitic, nodular; cryptocrystalline aggregates.
• Cleavage Type: None
• Fracture Type: Conchoidal to uneven
• Tenacity: Brittle
• Luster Type: Waxy to vitreous

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