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Formula: Ca2Y2(SiO3)4(CO3).H2O
Cyclosilicate (ring silicate), yttrium-bearing mineral
Crystal System: Orthorhombic
Specific gravity: 3.52 measured, 3.542 calculated
Hardness: 5 to 6
Streak: White
Colour: Chestnut brown, straw yellow, colourless
Solubility: Effervesces slowly in cold dilute hydrochloric acid
Common impurities: Na
Weakly RADIOACTIVE
Environments
Igneous environments
Pegmatites
Kainosite occurs in vugs in pegmatites in granite and alkaline complexes (HOM).
It may form from yttrialite-(Y) and pseudomorphs of
kainosite after yttrialite-(Y) have been found
(Dana).
Localities
At the Bancroft area, Ontario, Canada, some of the finest specimens of kainosite-(Y) have been found, associated with
chamosite, pyrite,
quartz, calcite,
sphalerite, fluorite,
uraninite, zircon and
molybdenite
(HOM, R&M 94.5.413-414).
At the Poudrette quarry, Mont Saint-Hilaire, La Vallée-du-Richelieu RCM, Montérégie, Quebec, Canada, kainosite-(Y) occurs in
cavities in breccia
(Dana).
At Baveno, Verbano-Cusio-Ossola Province, Piedmont, Italy, kainosite-(Y) occurs in granite
(Dana).
At Mount Malosa, Zomba, Southern Region, Malawi, a few crystals of kainosite-(Y) to 4 cm have been found on a matrix of
feldspar and aegirine
(Min Rec 35.3.255).
The type locality is the Igletjødn Feldspar Quarry, Hæstad, Hidra, Flekkefjord, Agder, Norway.
At the Nordmark District, Filipstad, Värmland County, Sweden, yellow-brown to chestnut-brown kainosite-(Y) occurs in an iron mine
associated with diopside, clinochlore,
magnetite and apatite
(Dana, HOM).
At the Bjørndalen Quarry, Tvedalen, Larvik, Vestfold og Telemark, Norway, kainosite-(Y) has been found only
once in syenite
pegmatite material at the
larvikite quarry. It occurs as beige-coloured radiating masses up
to 1 mm across in a calcite matrix. Associated minerals include
lorenzenite and
pyrophanite. The
pegmatite comprises
microcline, nepheline and
aegirine as the main minerals, plus abundant
mosandrite-(Ce) (partially decomposed),
pyrochlore and fluorite.
Kainosite-(Y) probably crystallised as a result of hydrothermal decomposition of
mosandrite-(Ce)
(JWW p163).
At the Porthill Mining District, Boundary county, Idaho, USA, colourless to white kainosite-(Y) has been discovered
in a thorite vein. Kainosite-(Y) is one of a small group of minerals in which
yttrium is a major constituent. The thorite vein in which
it occurs is intruded into a diorite sill and is made up chiefly of
quartz and thorite. Other minerals include
calcite, chlorite,
magnetite, allanite,
apatite and kainosite. Kainosite was found only in the vein material having the
highest radioactivity. It is commonly either adjacent to or intergrown with allanite, although
in places it is intergrown with calcite
(AM 49.1636-1741, as cenosite).
At the Grenci-Ellis Granite quarry, Mount Desert, Hancock county, Maine, USA, kainosite-(Y) occurs in a
granite pegmatite with
kamphaugite-(Y)
(Dana).
At Rossie, St. Lawrence county, New York, USA, kainosite-(Y) occurs in galena mines,
with calcite
(Dana).
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