How to identify Chlorite Included Quartz

To correctly identify Chlorite Included Quartz (SiO2 with Chlorite), 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

   Clear to milky white quartz with green, greenish-yellow, or brownish-green inclusions. The green color is characteristic of chlorite.

2. 2

   Luster

   How the surface reflects light: metallic, vitreous, dull

   Vitreous (glassy) for the quartz, dull to pearly for the chlorite inclusions.

3. 3

   Texture

   Grain size and surface feel: coarse, fine, glassy

   Smooth, hard surface of quartz, with potential for rougher or fibrous textures where chlorite is densely included or exposed.

4. 4

   Crystal Form

   Shape of visible crystals or crystal faces

   Typically hexagonal prisms terminated by rhombohedral faces for the quartz. Chlorite inclusions may follow the growth patterns of the quartz, forming 'phantoms', or appear as scattered flakes/aggregates.

5. 5

   Cleavage

   How it breaks: flat cleavage planes vs irregular fracture

   Quartz has no true cleavage, exhibiting conchoidal fracture. Chlorite has perfect basal cleavage (one direction).

6. 6

   Geological Environment

   The rock formation and setting where it occurs

   Hydrothermal veins, metamorphic rocks (schists, gneisses), igneous rocks (granites, pegmatites), often associated with low-grade metamorphism or alteration zones.

Key Facts

Hardness

7 (Mohs scale for quartz); 2-2.5 (Mohs scale for chlorite)

Specific Gravity

2.65 (for quartz); 2.6-3.3 (for chlorite, varies with composition)

Crystal System

Trigonal (for quartz); Monoclinic (for chlorite)

Color

Colorless to white (quartz) with green, greenish-yellow, or brownish-green inclusions (chlorite).

Luster

Vitreous (quartz); dull to pearly (chlorite)

Transparency

Transparent to translucent (quartz); opaque to translucent (chlorite inclusions)

Fracture

Conchoidal (quartz); uneven to splintery (chlorite)

Cleavage

None (quartz); Perfect basal (001) (chlorite)

Composition

SiO2 (Quartz) with various chlorite group minerals, typically (Mg,Fe)3(Si,Al)4O10(OH)2·(Mg,Fe)3(OH)6

Physical characteristics

• Crystal Habit: Quartz: Prismatic, often terminated with rhombohedral faces, massive, granular. Chlorite inclusions: Disseminated flakes, fibrous, mossy, or layered within quartz.
• Cleavage Type: Quartz: None. Chlorite: Perfect in one direction (basal).
• Fracture Type: Quartz: Conchoidal. Chlorite: Uneven to splintery.
• Tenacity: Quartz: Brittle. Chlorite: Flexible, inelastic.
• Luster Type: Quartz: Vitreous. Chlorite: Dull to pearly.

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