Images
Formula: Be2(BO3)(OH)
Anhydrous borate containing hydroxyl,
beryllium-bearing mineral
Specific gravity: 2.347 to 2.372
Hardness: 7½
Streak: White
Colour: Colourless, greyish, yellowish, colourless in transmitted light
Solubility: Soluble in HF
Environments
Hambergite is an uncommon accessory mineral in granite and
syenite
pegmatites. Associated minerals include
beryl, danburite,
apatite, spodumene,
zircon, fluorite,
feldspar and quartz
(HOM).
Although originally described from an alkaline syenite
pegmatite, the majority of hambergite occurrences are
in complex lithium-rich granite
pegmatites of the
elbaite or transitional
elbaite-lepidolite subtypes
(CM 36.441-446).
Localities
In the Czech Republic hambergite occurs as an early phase in massive
pegmatites from several localities or more commonly as a
late phase in miarolitic pockets. Minerals associated with hambergite include
manganese-rich elbaite,
albite, quartz,
K-feldspar, lepidolite,
topaz, beryl,
apatite and cookeite.
Hambergite formed simultaneously with hydrothermal minerals such as
bavenite, herderite and
danburite, but prior to zeolites
and clay minerals.
The Czech elbaite-bearing
pegmatites are characterised by rare occurrence of
micas, the presence of manganese-rich
elbaite, and dominance of K-feldspar
over albite
(CM 36.441-446).
At the type locality, Salbutangen, Helgeroa, Langesundsfjorden, Larvik, Vestfold og Telemark, Norway, hambergite
occurs in a syenite
pegmatite associated with zircon,
sodalite, fluorite,
ferro-hornblende, feldspar,
biotite and analcime
(Mindat).
At Stak Nala, Haramosh Mountains, Roundu District, Gilgit-Baltistan, Pakistan, twin crystals of hambergite
have been found
attached to prisms of tricolored elbaite. Both minerals are partially
coated with white fine-grained boron-rich
muscovite. This assemblage is consistent with formation in a pocket
environment in a granite
pegmatite
(CM 34.615-621).
At the Little Three Mine, Ramona, Ramona Mining District, San Diego County, California, USA, in the section of the
dike in which hambergite was found, cleavelandite was common
and formed typical rounded growths between light smoky quartz crystals. The
hambergite was found in small nests several inches in diameter, growing on
quartz and cleavelandite.
Several of the quartz crystals had either implanted or completely embedded
hambergite crystals. Aside from quartz the mineral most intimately
associated with hambergite is cookeite. Other associated minerals are
lepidolite and topaz. These
associations point to a genesis for hambergite earlier than the pocket
quartz, microcline perthite and
topaz, but later than cleavelandite,
which was found penetrating hambergite crystals
(AM 50.85-95).
Back to Minerals