Rock Identifier
Aquamarine in pegmatite (Beryl, Be₃Al₂Si₆O₁₈ (blue-green variety: aquamarine)) — mineral
mineral

Aquamarine in pegmatite

Beryl, Be₃Al₂Si₆O₁₈ (blue-green variety: aquamarine)

AI-generated identification · may be incorrect

The central crystal appears pale blue-green, translucent, and prismatic with flat faces, consistent with beryl; the matrix is quartz-rich pegmatite with mica and feldspar. Beryl has Mohs hardness 7.5–8, vitreous luster, hexagonal crystal symmetry, and poor-to-indistinct cleavage; specific gravity is about 2.63–2.80.

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Physical properties

The central crystal appears pale blue-green, translucent, and prismatic with flat faces, consistent with beryl; the matrix is quartz-rich pegmatite with mica and feldspar. Beryl has Mohs hardness 7.5–8, vitreous luster, hexagonal crystal symmetry, and poor-to-indistinct cleavage; specific gravity is about 2.63–2.80.

Formation & geological history

Forms in late-stage, water-rich granitic pegmatites as magma cools and concentrates beryllium. Most specimens formed during Precambrian to Mesozoic pegmatite activity, depending on locality.

Uses & applications

Transparent aquamarine is cut for jewelry; larger crystals are collector specimens. Pegmatite minerals are also important sources of quartz, feldspar, mica, and occasionally lithium-related minerals.

Geological facts

The blue-green color generally comes from iron impurities. The specimen may also contain altered feldspar, smoky or milky quartz, and mica; exact identification would benefit from a hardness, refractive-index, or laboratory test.

Field identification & locations

Look for six-sided prismatic crystals, pale blue-green color, glassy luster, and hardness sufficient to scratch glass, embedded in coarse pegmatite. Common sources include Brazil, Pakistan, Afghanistan, Madagascar, Russia, and Colorado, USA.