How to identify Amazonite with Smoky Quartz

To correctly identify Amazonite with Smoky Quartz (Amazonite (variety of Microcline Feldspar) with Smoky Quartz), 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

   Amazonite: Blue-green to greenish-blue, sometimes with white streaks. Smoky Quartz: Translucent to opaque gray, brown, or black.

2. 2

   Luster

   How the surface reflects light: metallic, vitreous, dull

   Vitreous (glassy) for both amazonite and smoky quartz.

3. 3

   Texture

   Grain size and surface feel: coarse, fine, glassy

   Typically crystalline, often with large, well-formed crystals. Amazonite may show fine striations or perthitic textures. Smoky quartz can be massive or form distinct prismatic crystals.

4. 4

   Crystal Form

   Shape of visible crystals or crystal faces

   Amazonite: Triclinic, typically forming blocky to tabular crystals, often twinned. Smoky Quartz: Hexagonal, typically forming prismatic crystals with pyramidal terminations.

5. 5

   Cleavage

   How it breaks: flat cleavage planes vs irregular fracture

   Amazonite: Two distinct cleavages at nearly 90 degrees (perfect on {001} and good on {010}). Smoky Quartz: No cleavage, exhibits conchoidal fracture.

6. 6

   Geological Environment

   The rock formation and setting where it occurs

   Granitic pegmatites, particularly those enriched in rare elements. Also found in some granites and syenites.

Key Facts

Hardness

Amazonite: 6-6.5 (Mohs). Smoky Quartz: 7 (Mohs).

Specific Gravity

Amazonite: 2.56-2.58. Smoky Quartz: 2.65-2.69.

Crystal System

Amazonite: Triclinic. Smoky Quartz: Hexagonal (Trigonal).

Color

Amazonite: Blue-green to greenish-blue. Smoky Quartz: Gray to brownish-black.

Luster

Vitreous.

Transparency

Translucent to opaque.

Fracture

Amazonite: Uneven to conchoidal. Smoky Quartz: Conchoidal.

Cleavage

Amazonite: Perfect on {001}, good on {010}. Smoky Quartz: None.

Composition

Amazonite: KAlSi3O8 (Potassium Aluminum Silicate). Smoky Quartz: SiO2 (Silicon Dioxide).

Physical characteristics

• Crystal Habit: Amazonite: Prismatic, tabular, blocky, often twinned. Smoky Quartz: Prismatic with pyramidal terminations, massive.
• Cleavage Type: Amazonite: Two distinct cleavages at nearly 90 degrees. Smoky Quartz: Absent.
• Fracture Type: Amazonite: Uneven to conchoidal. Smoky Quartz: Conchoidal.
• Tenacity: Brittle for both.
• Luster Type: Vitreous.

Explore Amazonite with Smoky Quartz