How to identify K2 Jasper

To correctly identify K2 Jasper (Granite with Azurite and minor Malachite), 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

   White to grey granitic matrix with distinct, often spherical, bright blue azurite inclusions. Minor green malachite may also be present.

2. 2

   Luster

   How the surface reflects light: metallic, vitreous, dull

   Granite matrix is typically vitreous to dull; azurite is vitreous to dull; malachite is silky to dull.

3. 3

   Texture

   Grain size and surface feel: coarse, fine, glassy

   Granular, phaneritic (coarse-grained) texture typical of granite, with distinct, often rounded, inclusions of azurite.

4. 4

   Crystal Form

   Shape of visible crystals or crystal faces

   Granite minerals (quartz, feldspar, mica) are anhedral to subhedral. Azurite typically occurs as disseminated grains, spherulitic aggregates, or botryoidal masses within the granite. Malachite occurs similarly.

5. 5

   Cleavage

   How it breaks: flat cleavage planes vs irregular fracture

   Granite minerals exhibit cleavage (feldspar: two directions at 90 degrees; mica: one perfect basal cleavage). Azurite has good cleavage in one direction. Malachite has perfect cleavage in one direction.

6. 6

   Geological Environment

   The rock formation and setting where it occurs

   Intrusive igneous environments where granite has formed, subsequently undergoing hydrothermal alteration and mineralization by copper-rich fluids.

Key Facts

Hardness

Granite matrix: 6-7 (Mohs). Azurite inclusions: 3.5-4 (Mohs). Malachite inclusions: 3.5-4 (Mohs).

Specific Gravity

Granite: 2.6-2.7 g/cm³. Azurite: 3.77-3.89 g/cm³. Malachite: 3.9-4.03 g/cm³.

Crystal System

Granite minerals: Quartz (trigonal), Feldspar (monoclinic/triclinic), Mica (monoclinic). Azurite: Monoclinic. Malachite: Monoclinic.

Color

White, grey, or light brown granite with vivid blue (azurite) and sometimes green (malachite) spots.

Luster

Vitreous to dull for granite and azurite; silky to dull for malachite.

Transparency

Opaque.

Fracture

Granite: uneven to conchoidal. Azurite: conchoidal. Malachite: subconchoidal to uneven.

Cleavage

Granite minerals: Feldspar (good in two directions), Mica (perfect basal). Azurite: good in one direction. Malachite: perfect in one direction.

Composition

Predominantly SiO2, Al2O3, K2O, Na2O (from granite) with Cu3(CO3)2(OH)2 (azurite) and Cu2CO3(OH)2 (malachite).

Physical characteristics

• Crystal Habit: Granite: Granular, massive. Azurite: Massive, botryoidal, spherulitic, or as disseminated grains. Malachite: Massive, botryoidal, fibrous, or as crusts.
• Cleavage Type: Granite: Feldspar (prismatic), Mica (basal). Azurite: Prismatic. Malachite: Basal.
• Fracture Type: Granite: Uneven to conchoidal. Azurite: Conchoidal. Malachite: Subconchoidal to uneven.
• Tenacity: Brittle.
• Luster Type: Vitreous, dull, silky.

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