How to identify Azurite with Malachite

To correctly identify Azurite with Malachite (Azurite (Cu3(CO3)2(OH)2) and Malachite (Cu2CO3(OH)2)), 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

   Azurite: Deep azure-blue to violet-blue. Malachite: Bright green to dark green, often banded. The combination will show both colors.

2. 2

   Luster

   How the surface reflects light: metallic, vitreous, dull

   Vitreous to dull, sometimes silky in fibrous malachite.

3. 3

   Texture

   Grain size and surface feel: coarse, fine, glassy

   Can be massive, botryoidal, stalactitic, or as radiating fibrous aggregates. Individual azurite crystals can be prismatic or tabular. Malachite often forms mammillary or botryoidal masses with concentric banding.

4. 4

   Crystal Form

   Shape of visible crystals or crystal faces

   Azurite: Monoclinic, typically as tabular or prismatic crystals, also massive, granular, or botryoidal. Malachite: Monoclinic, commonly botryoidal, mammillary, stalactitic, or fibrous aggregates; rarely as acicular crystals.

5. 5

   Cleavage

   How it breaks: flat cleavage planes vs irregular fracture

   Azurite: Perfect on {011}, good on {100}. Malachite: Perfect on {201}, good on {010}.

6. 6

   Geological Environment

   The rock formation and setting where it occurs

   Oxidized zones of copper ore deposits, often associated with limestones or dolomites, where carbonic acid is readily available for carbonate formation.

Key Facts

Hardness

Azurite: 3.5-4 on Mohs scale. Malachite: 3.5-4 on Mohs scale.

Specific Gravity

Azurite: 3.77-3.89. Malachite: 3.9-4.03.

Crystal System

Monoclinic for both azurite and malachite.

Color

Azurite: Azure-blue, deep blue. Malachite: Bright green, dark green.

Luster

Vitreous to dull, silky (especially fibrous malachite).

Transparency

Transparent to opaque.

Fracture

Conchoidal to uneven.

Cleavage

Azurite: Perfect on {011}, good on {100}. Malachite: Perfect on {201}, good on {010}.

Composition

Azurite: Copper carbonate hydroxide (Cu3(CO3)2(OH)2). Malachite: Copper carbonate hydroxide (Cu2CO3(OH)2).

Physical characteristics

• Crystal Habit: Azurite: Tabular, prismatic, massive, granular, botryoidal. Malachite: Botryoidal, mammillary, stalactitic, fibrous, massive, rarely acicular crystals.
• Cleavage Type: Azurite: Distinct to perfect. Malachite: Distinct to perfect.
• Fracture Type: Conchoidal to uneven.
• Tenacity: Brittle.
• Luster Type: Vitreous, silky, dull.

Explore Azurite with Malachite