How to identify Aquamarine and Pearl

To correctly identify Aquamarine and Pearl (Beryl (Aquamarine variety) and Calcium Carbonate (Pearl)), 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

   Aquamarine: Blue to blue-green; Pearl: White, cream, pink, silver, black, often with overtone colors.

2. 2

   Luster

   How the surface reflects light: metallic, vitreous, dull

   Aquamarine: Vitreous; Pearl: Pearly (nacreous).

3. 3

   Texture

   Grain size and surface feel: coarse, fine, glassy

   Aquamarine: Smooth, glassy; Pearl: Smooth, sometimes slightly bumpy, with a characteristic 'gritty' feel when rubbed against a tooth (for natural/cultured pearls).

4. 4

   Crystal Form

   Shape of visible crystals or crystal faces

   Aquamarine: Hexagonal prisms, often with striations parallel to the c-axis; Pearl: Spherical, oval, baroque, button, drop, or ringed shapes, lacking crystal faces.

5. 5

   Cleavage

   How it breaks: flat cleavage planes vs irregular fracture

   Aquamarine: Imperfect basal cleavage {0001}; Pearl: No cleavage, conchoidal fracture.

6. 6

   Geological Environment

   The rock formation and setting where it occurs

   Aquamarine: Granitic pegmatites, hydrothermal veins, metamorphic rocks; Pearl: Marine and freshwater mollusk shells.

Key Facts

Hardness

Aquamarine: 7.5-8 on Mohs scale; Pearl: 2.5-4.5 on Mohs scale.

Specific Gravity

Aquamarine: 2.68-2.80; Pearl: 2.60-2.85 (natural), 2.70-2.78 (cultured).

Crystal System

Aquamarine: Hexagonal; Pearl: Orthorhombic (aragonite) or trigonal (calcite) microcrystalline layers.

Color

Aquamarine: Blue, blue-green; Pearl: White, cream, pink, silver, black, yellow, green, blue.

Luster

Aquamarine: Vitreous; Pearl: Pearly (nacreous).

Transparency

Aquamarine: Transparent to translucent; Pearl: Opaque to translucent.

Fracture

Aquamarine: Conchoidal to uneven; Pearl: Conchoidal.

Cleavage

Aquamarine: Imperfect basal {0001}; Pearl: None.

Composition

Aquamarine: Beryllium aluminum silicate; Pearl: Calcium carbonate (aragonite/calcite) and conchiolin.

Physical characteristics

• Crystal Habit: Aquamarine: Prismatic, columnar, often striated; Pearl: Spherical, oval, baroque, irregular aggregates of nacre.
• Cleavage Type: Aquamarine: Imperfect basal; Pearl: None.
• Fracture Type: Aquamarine: Conchoidal to uneven; Pearl: Conchoidal.
• Tenacity: Aquamarine: Brittle; Pearl: Tough.
• Luster Type: Aquamarine: Vitreous; Pearl: Pearly (nacreous).

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