Genesis and growth of the red beryl from Utah (U.S.A.)

Hydrothermal Synthetic Red Beryl from the Institute of Crystallography, Moscow

“…The presence of other elements gives rise to various colors (Fe, Cr, V, and Mn for coloration in H Shigley and Foord, 1984). The crystals formed in fractures within devitrified rhyolite lava, probably as a result of the metasomatic reaction between a fluorine-rich gas or vapor phase and potassium feldspar (Aurisicchio et al, 1990;Henn and Becker, 1995). These crystals are often chemically zoned, which can result in an uneven coloration.…”

“…The color of faceted material ranges from purplish red to red to orangered. Compared to most other beryls, red beryl is enriched in Mn, Fe, Ti, Rb, Zn, and Sn, and is depleted in Na, K, and Mg. Red beryl is noted for its almost complete absence of water Aurisicchio et al, 1990), which is also unique among beryls that typically crystallize in hydrothermal geological environments.…”

“…Henn and Milisenda (1999) described hydrothermal synthetic red beryl from an unstated source in Russia that has many gemological properties in common with the material described here. Although similar in overall appearance, the synthetic product differs in gemological properties from natural red beryl (for descriptions of the latter, see Schmetzer et al, 1974;Miley, 1980;Flamini et al, 1983;Shigley and Foord, 1984;Aurisicchio et al, 1990;Hosaka et al, 1993;Harding, 1995).…”

Red Beryl from Utah: A Review and Update

“…Hexagonal growth zoning can be seen in some cut stones viewed in a direction parallel to the c-axis (figure 14). Mineral inclusions consist of colorless to white quartz and feldspar, and black grains of hematite or bixbyite (Shigley and Foord, 1984;Aurisicchio et al, 1990). One stone revealed an unusual spray of needle-like tubes that were filled with what is probably goethite (figure 15).…”

“…chemically reacted with rhyolitic glass, alkali feldspar, and Fe-Mn oxide minerals (bixbyite) along the fractures, primarily as a replacement of alkali feldspar (see also Aurisicchio et al, 1990;Barton and Young, 2002). * As temperatures continued to drop, subsequent reactions produced an acidic aqueous fluid that caused clay alteration along the fractures and within portions of the rhyolite.…”