How to identify Native Copper with Malachite and Azurite

To correctly identify Native Copper with Malachite and Azurite (Cu (Native Copper) with Cu2(CO3)(OH)2 (Malachite) and Cu3(CO3)2(OH)2 (Azurite)), 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

   Native Copper: Copper-red, tarnishing to dark brown or green. Malachite: Bright green to dark green. Azurite: Azure blue to deep blue.

2. 2

   Luster

   How the surface reflects light: metallic, vitreous, dull

   Native Copper: Metallic. Malachite: Silky, dull, or earthy. Azurite: Vitreous to dull or earthy.

3. 3

   Texture

   Grain size and surface feel: coarse, fine, glassy

   Native Copper: Massive, dendritic, arborescent, wire-like. Malachite: Botryoidal, stalactitic, fibrous, massive, earthy. Azurite: Prismatic crystals, radiating aggregates, massive, earthy.

4. 4

   Crystal Form

   Shape of visible crystals or crystal faces

   Native Copper: Isometric system, often distorted cubes, octahedra, or dodecahedra, but more commonly massive or dendritic. Malachite: Monoclinic system, typically botryoidal or fibrous aggregates, rarely distinct crystals. Azurite: Monoclinic system, often well-formed prismatic crystals, also massive or earthy.

5. 5

   Cleavage

   How it breaks: flat cleavage planes vs irregular fracture

   Native Copper: None. Malachite: Perfect on {201}, good on {010}. Azurite: Perfect on {021}, good on {100}.

6. 6

   Geological Environment

   The rock formation and setting where it occurs

   Oxidized zones of copper sulfide deposits, often associated with limestones or other carbonate-rich host rocks, where groundwater interacts with primary copper minerals and atmospheric CO2.

Key Facts

Hardness

Native Copper: 2.5-3 (Mohs). Malachite: 3.5-4 (Mohs). Azurite: 3.5-4 (Mohs).

Specific Gravity

Native Copper: 8.94-8.95. Malachite: 3.9-4.03. Azurite: 3.77-3.89.

Crystal System

Native Copper: Isometric. Malachite: Monoclinic. Azurite: Monoclinic.

Color

Native Copper: Copper-red, tarnishing to dark brown or green. Malachite: Bright green to dark green. Azurite: Azure blue to deep blue.

Luster

Native Copper: Metallic. Malachite: Silky, dull, or earthy. Azurite: Vitreous to dull or earthy.

Transparency

Native Copper: Opaque. Malachite: Opaque. Azurite: Translucent to opaque.

Fracture

Native Copper: Hackly. Malachite: Uneven to subconchoidal. Azurite: Conchoidal to uneven.

Cleavage

Native Copper: None. Malachite: Perfect on {201}, good on {010}. Azurite: Perfect on {021}, good on {100}.

Composition

Native Copper: Elemental Copper (Cu). Malachite: Copper Carbonate Hydroxide (Cu2(CO3)(OH)2). Azurite: Copper Carbonate Hydroxide (Cu3(CO3)2(OH)2).

Physical characteristics

• Crystal Habit: Native Copper: Massive, dendritic, arborescent, wire-like, rarely distinct crystals. Malachite: Botryoidal, stalactitic, fibrous, massive, earthy. Azurite: Prismatic crystals, radiating aggregates, massive, earthy.
• Cleavage Type: Native Copper: Absent. Malachite: Perfect in one direction, good in another. Azurite: Perfect in one direction, good in another.
• Fracture Type: Native Copper: Hackly. Malachite: Uneven to subconchoidal. Azurite: Conchoidal to uneven.
• Tenacity: Native Copper: Ductile and malleable. Malachite: Brittle. Azurite: Brittle.
• Luster Type: Native Copper: Metallic. Malachite: Silky, dull, earthy. Azurite: Vitreous, dull, earthy.

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