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Formula: NaSc3+Si2O6
Inosilicate (chain silicate), single chains,
clinopyroxene subgroup,
pyroxene group,
scandium-bearing mineral
Crystal System: Monoclinic
Specific gravity: 3.31 calculated
Hardness: 6
Streak: White
Colour: Light green
Common impurities: Ti,Al,Mn
Environments
Localities
At the type locality, the Giacomini Quarry, Agrano, Omegna, Verbano-Cusio-Ossola Province, Piedmont, Italy, two new
(in 1982) mineral phases, cascandite and
jervisite, join kolbeckite
and thortveitite as rare minerals in which
scandium occurs as an essential, major constituent. It seems remarkable
that three of these four scandium silicates (not
kolbeckite) were found in the
granite of Baveno.
The rarity of scandium minerals is a result of its crystal chemical
behaviour; the bulk of the element is dispersed in very small amounts among minerals formed in the early stages of
magmatic differentiation, mainly pyroxenes,
amphiboles and biotite; only a
very small amount passes through the magmatic stage and enters pegmatitic, pneumatolitic and hydrothermal deposits
(AM 67.599-603).
Jervisite occurs in miarolitic cavities in granite, associated
with cascandite, quartz,
orthoclase and albite
(HOM).
Jervisite from the Baveno granites -
Image
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