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Formula: Na2Si4O8(OH)2.4H2O
Hydrated phyllosilicate (sheet silicate)
Crystal System: Monoclinic
Specific gravity: 1.97 to 2.07 measured, 2.05 calculated
Streak: White
Colour: White
Solubility: Insoluble in water
Common impurities: Ti,Al,Fe,Mg,Ca,K
Environments
Localities
At the Poudrette quarry, Mont Saint-Hilaire, La Vallée-du-Richelieu RCM, Montérégie, Québec, Canada, makatite
is associated with vuonnemite,
sodalite, ussingite,
aegirine, steenstrupine,
eudialyte and lovozerite
(HOM).
Makatite from the Poudrette Quarry -
Image
At the Saint-Amable sill, Varennes & St-Amable, Lajemmerais RCM, Montérégie, Québec, Canada, makatite
is associated with varennesite,
eudialyte, zakharovite,
shkatulkalite and magadiite
(HOM).
Makatite from the Saint-Amable sill -
Image
The type locality, Lake Magadi, Kajiado County, Kenya, is a sodium carbonate-bicarbonate lake that in 1970 was
precipitating trona and halite. The
lake is underlain by a thick deposit of trona and interbedded
tuffaceous claystone.
Makatite was found in cores from holes drilled in 1953. In one core, makatite occurs at depths of
46 to 60 feet and 88.5 to 96 feet. It is commonly associated with
magadiite in the upper sequence, but makatite is generally the
only water-insoluble mineral in the lower sequence. Gaylussite,
anorthoclase and erionite
also occur locally with makatite in the same core samples. The makatite content of the core samples
ranges from less than 1 percent to about 50 percent. Makatite was also identified in
trona at a depth of 31 feet in another drill hole and at a depth of 27 feet
in a third drill hole.
The makatite occurs as white spherulites or radiating acicular aggregates that fill or partly fill cavities
in the coarsely crystalline trona. The spherulites are 0.05 to 0.3 mm in diameter and individual crystals are
0.05 to 2.0 µm wide and 5 to 30 µm long. Makatite commonly replaces
trona and is locally
pseudomorphous after bladed
trona. The pseudomorphs are
spongy in appearance because of the spherulitic character of the makatite
(AM 55.358-366)).
At the Alluaiv Mountain, Lovozersky District, Murmansk Oblast, Russia, makatite was leached from
natrosilite in an alkalic
pegmatite in the differentiated alkalic massif, where it
occurs associated with natrolite
(HOM).
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