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Formula: Na2Si22O41(OH)8.6H2O
Hydrated unclassified silicate
Crystal system: Monoclinic
Specific gravity: 2.33 calculated
Colour: White
Solubility: Treatment with dilute acid at room temperature yields a hydrous form of silica, near
6SiO2.H2O,
Common impurities: Ti,Al,Fe,Mn,Ca,K
Environments
Volcanic igneous environments
Precipitates from brine
The hydrous sodium silicate kenyaite can be synthesised from aqueous suspensions containing SiO2 and
NaOH with SiO2/NaOH ratios ranging from 5 to 20 and H2O/NaOH ratios from 50 to 500 at 100 to
150oC. This phase can also be prepared from concentrated
or diluted water glass (sodium silicate) solutions above 120oC. At 100oC
magadiite generally precipitates as the first reaction product and then alters
to kenyaite. The stable end product is quartz. Formation of
kenyaite at 100oC requires several months. The reaction times are much decreased at higher temperatures
but under these conditions quartz forms rapidly. Synthetic kenyaites form
spherical aggregates of well-developed plates
(AM 68.818-826)
Localities
At the type locality, Lake Magadi, Kajiado County, Kenya, kenyaite occurs in nodular concretions, sometimes with
cores of chert, in the magadiite
beds, and was evidently formed by the leaching of magadiite
(AM 53.510).
Kenyaite from Lake Magadi - Image
The Trinity Mining claim, Wildcat Peak, Halls Gulch Mining District, Trinity Mountains, Klamath Mountains, Trinity
County, California, USA, unlike the Lake Magadi kenyaite occurrence, is not associated with an alkaline lake, but
with altered volcanic rocks
(AM 53.2061-2069).
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