How to identify Aquamarine

To correctly identify Aquamarine (Be3Al2Si6O18), 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

   Ranges from pale blue to deep blue-green. The color is typically uniform, though some zoning can occur. The most prized color is a deep, saturated blue.

2. 2

   Luster

   How the surface reflects light: metallic, vitreous, dull

   Vitreous (glassy).

3. 3

   Texture

   Grain size and surface feel: coarse, fine, glassy

   Smooth to the touch on crystal faces; conchoidal fracture surfaces are smooth and curved.

4. 4

   Crystal Form

   Shape of visible crystals or crystal faces

   Typically forms hexagonal prisms, often with flat pinacoid terminations. Crystals can be columnar, massive, or granular. Striations parallel to the c-axis are common on prism faces.

5. 5

   Cleavage

   How it breaks: flat cleavage planes vs irregular fracture

   Imperfect basal cleavage (0001), often not observed in hand specimens or fractured pieces.

6. 6

   Geological Environment

   The rock formation and setting where it occurs

   Found primarily in granitic pegmatites, especially those rich in lithium and tin. Also occurs in hydrothermal veins and in alluvial deposits derived from these primary sources.

Key Facts

Hardness

7.5-8 on the Mohs scale

Specific Gravity

2.68-2.80 g/cm³

Crystal System

Hexagonal

Color

Blue to blue-green

Luster

Vitreous

Transparency

Transparent to translucent

Fracture

Conchoidal to uneven

Cleavage

Imperfect basal (0001)

Composition

Beryllium aluminum cyclosilicate (Be3Al2Si6O18)

Physical characteristics

• Crystal Habit: Prismatic, columnar, massive, granular. Often forms well-developed hexagonal prisms, sometimes with striations parallel to the c-axis.
• Cleavage Type: Imperfect on {0001}. Typically not a prominent feature and rarely observed in fractured specimens.
• Fracture Type: Conchoidal to uneven. Breaks with smooth, curved surfaces or irregular, rough surfaces.
• Tenacity: Brittle. It will break or chip under impact.
• Luster Type: Vitreous (glassy). Some specimens may exhibit a resinous luster on fracture surfaces.

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