Aquamarine

Hardness: 7.5-8 on the Mohs scale. Color: Pale blue, light blue, or bluish-green. Luster: Vitreous (glassy). Crystal Structure: Hexagonal; often forms prismatic crystals. Cleavage: Imperfect basal {0001}. Specific Gravity: 2.68-2.76.

Aquamarine forms in pegmatites, which are igneous rocks characterized by very large crystals. It also occurs in hydrothermal veins and alluvial deposits. The blue color is typically due to trace amounts of iron within the beryl structure. The geological age of aquamarine deposits varies widely, from Precambrian to Cenozoic, depending on the specific geological formations where they are found.

Predominantly used as a gemstone in jewelry due to its attractive color and good hardness. It is often cut into various shapes, including emerald cut, oval, and round. Larger, clear specimens are particularly valued. It's not typically used in industry or construction.

The name 'aquamarine' is derived from the Latin words 'aqua marina,' meaning 'water of the sea,' referring to its ocean-like color. Historically, sailors believed aquamarine would protect them at sea. The largest aquamarine ever found, the 'Minas Gerais' aquamarine, weighed 110 kg and was discovered in Brazil. Brazil is a major source of high-quality aquamarines.

In the field, aquamarine can be identified by its distinctive blue to bluish-green color, vitreous luster, and hexagonal crystal habit when found in its natural crystal form. Its hardness (able to scratch glass) helps distinguish it from softer blue minerals. Common locations include Brazil (especially Minas Gerais), Pakistan, Nigeria, Madagascar, Zambia, and the United States (Colorado). For collectors, identifying natural, untreated stones and understanding the purity of the color are key.