bertrandite

mineral

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July 20, 2026

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Bertrandite is a mineral composed of beryllium silicate with the chemical formula Be₄Si₂O₇(OH)₂. It typically appears as hard, colorless to pale-yellow prismatic crystals and has a hardness of 6–7. Bertrandite is one of the minerals, along with beryl, that serves as a commercial source of beryllium. Beryllium is a light, steel-gray metal with various applications, including as a hardening agent in metallurgy and in aerospace and nuclear technologies. While beryl is a primary source of beryllium, bertrandite also contains this element, though in smaller quantities.123

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beryllium
Occurrence, properties, and uses
…(Al₂Be₃Si₆O₁₈, a beryllium aluminum silicate), bertrandite (Be₄Si₂O₇(OH)₂, a beryllium silicate), phenakite (Be₂SiO₄), and chrysoberyl (BeAl₂O₄). (The precious forms of beryl, emerald and aquamarine, have a composition closely approaching that given above, but industrial ores contain less beryllium; most beryl is obtained as a by-product of
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…(Al₂Be₃Si₆O₁₈, a beryllium aluminum silicate), bertrandite (Be₄Si₂O₇(OH)₂, a beryllium silicate), phenakite (Be₂SiO₄), and chrysoberyl (BeAl₂O₄). (The precious forms of beryl, emerald and aquamarine, have a composition closely approaching that given above, but industrial ores contain less beryllium; most beryl is obtained as a by-product of
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