Bazzite

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Formula: Be₃(Sc,Fe³⁺,Mg)₂Si₆O₁₈.Na_0.32.nH₂O
Cyclosilicate (ring silicate), beryl group, beryllium-bearing mineral
Crystal System: Hexagonal
Specific gravity: 2.77 to 2.8 measured, 2.82 calculated
Hardness: 6½ to 7
Streak: White
Colour: Deep blue or other shades of blue, blue-green; colourless at Canadian localities
Common impurities: Fe,Mn,Mg,Li,Na,K,Rb,Cs
Environments

Plutonic igneous environments
Pegmatites
Hydrothermal environments

Bazzite is found in miarolitic cavities in granite, granite pegmatites and in Alpine veins associated with pegmatitic minerals.
The blue colour is caused by appreciable iron contents, and the intensity of the colour is determined by the ratio of Fe²⁺ to Fe³⁺ (Mindat).

Localities

At the Bugaboo Castles, Golden Mining Division, British Columbia, Canada, the Bugaboo Batholith comprises two main phases: an earlier hornblende-biotite granodiorite in the west and a biotite granite in the east. The western granodiorite is fine to medium-grained and contains hornblende, biotite, microcline, quartz and plagioclase. The eastern granite is medium to coarse-grained, variably porphyritic with phenocrysts of microcline and a matrix of microcline, quartz, plagioclase and biotite. Pegmatites, miarolitic cavities, and aplitic dikes can be found both internal and external to the eastern granite. The batholith is surrounded by a contact metamorphic aureole 1 km wide with hornfels, phyllites, schists, and minor migmatite zones close to the contact with the granite, as well as a previously unknown skarn.
The pegmatites are simply zoned and show evidence of late-stage replacement or alteration by metasomatic fluids. The core zone of most of the pegmatites and miarolitic cavities contains quartz, microcline, schorl, and muscovite, with minor albite, beryl, chamosite, epidote and spessartine. The pegmatites can be classified as muscovite-rare element pegmatite, beryl or beryl-tourmaline subtype.
Bazzite occurs in a replacement zone observed in only a single pegmatite. Alteration or metasomatism of primary spessartine, beryl and muscovite resulted in a secondary assemblage of bazzite, bertrandite, cookeite, secondary muscovite, and a clay mineral. The bazzite crystals are colourless, hexagonal prisms terminated by a pinacoid. It is interesting to note that both the Ontario and BC bazzite are colourless; all bazzite described in the literature to date (June 2024) is varying shades of blue (CJMP 62.3.457-478).

The Rose Quartz Pit, Quadeville area, Lyndoch Township, Brudenell-Lyndoch-and-Raglan, Renfrew County, Ontario, Canada, is one of a suite of rare-earth-element-enriched granitic pegmatites consisting mainly of quartz, plagioclase, and K-feldspar, with lesser biotite and garnet; muscovite and rare element minerals are accessory phases when present at all. Pegmatites containing beryl and columbite group minerals, including the Rose Quartz pegmatite, represent late-stage fractionation products of the pegmatite melts enriched in rare elements.
The Quadeville Rose Quartz pegmatite is well-zoned, with three recognisable units:
(1) a wall zone containing microcline, albite and quartz
(2) an intermediate zone of microcline and quartz
(3) a quartz core, which ranges in colour from colourless to white to smoky to rose-coloured
The quartz and microcline reach impressive sizes, with microcline crystals up to 8 x 2.5 x 2 m³ and a rose quartz crystal in the core measuring in at 2 x 5 x 10 m³. The mineralogy is dominated by quartz and microcline, with accessory augite, beryl, euxenite-(Y), columbite-(Fe) and kaolinite in the wall and intermediate zones. Additional accessory phases identified over the last decades include albite, bazzite, bertrandite, fluorite, hematite, magnetite, pyrite, samarskite-(Y) and zircon.
Bazzite occurs in altered miarolitic cavities in white microcline. Crystals are colourless, hexagonal prismatic to acicular, and terminated by a pinacoid. They occur as clusters of single crystals, 0.2 to 0.6 mm in length and 0.02 to 0.12 mm in width, on a matrix of quartz and microcline with aeschynite, bertrandite, chamosite, hematite, montmorillonite and nontronite (CJMP 62.3.457-478).
Bazzite from the Rose Quartz Pit - Image

At the type Locality, the Seula mine, Mount Camoscio, Oltrefiume, Baveno, Verbano-Cusio-Ossola Province, Piedmont, Italy, bazzite occurs in miarolitic cavities in granite, associated with quartz, orthoclase, muscovite, laumontite and albite (HOM).
Bazzite from the Seula Mine - Image

At the Heftetjern pegmatite, Tørdal, Drangedal, Vestfold og Telemark, Norway, bazzite occurs in the granite pegmatite associated with beryl and bavenite (HOM).
Bazzite from Heftetjern - Image

At Val Strem, Tujetsch, Surselva Region, Grisons, Switzerland, bazzite occurs in alpine veins associated with quartz, hematite, calcite, chlorite, albite and fluorite (HOM).

At the Farview area, Mount Rosa, El Paso county, Colorado, USA, beryl is absent, but late-stage to secondary beryllium-bearing minerals are present. Bazzite occurs in small vugs within a quartz vein, associated with pyrite, magnetite and goethite (R&M 95.3.271-272).

In New Hampshire, USA, bazzite has been reported from the Government pit Albany, North Sugarloaf Mountain Bethlehem and Iron Mountain mine Bartlett. The bazzite occurs in NYF pegmatites as minute, transparent, intensely blue crystals less than 2 mm long. The crystals are found in small miaroles associated with quartz, albite and sometimes other beryllium species (R&M 97.2.211-212).
Bazzite from the Iron Mountain Mines - Image

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