alkali feldspar


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Related to alkali feldspar: Plagioclase feldspar, quartz, hornblende, K feldspar

alkali feldspar

n.
Any of a series of feldspars, consisting primarily of a mixture of sodium aluminum silicate, NaAlSi3O8, and potassium aluminum silicate, KAlSi3O8.
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11La(W)###Coarse###Angular-###Moderately###Grain###Ferruginous###Plagioclase, alkali Feldspar,
Also present were small transparent grey grains (with a distinctly higher lustre) of alkali feldspar that contained tiny metallic hematite flakes and small orange patches, possibly iron hydroxide.
Phenocrysts of plagioclase and hornblende along with alkali feldspar, quartz and ores are embedded in felsophyric groundmass.
The present work evaluates adsorption potential of alkali feldspar towards Direct Red 16 (synthetic textile dye).
Dominance of plagioclase feldspar over alkali feldspar is interpreted as being the result of high volcanic input.
In terms of mineral composition, the granite consist of major felsic minerals: quartz (33 %), plagioclase (29 %) and alkali feldspar (27 %).
They are composed of euhedral to subhedral, coarsely perthitic alkali feldspar and varying amounts of interstitial quartz (Fig.
The separated but matching adjacent grain boundaries in fractured quartz and residual alkali feldspar grains in saprolite are indicative of minor pedoplasmation.
The latter comprise plagioclase feldspar, alkali feldspar, quartz, and amphibole that has almost all altered to biotite mica.
As a rule, the alkali feldspar measurements give somewhat higher ages than OSL from quartz, which can be explained by slower bleaching of the feldspar in the sunlight exposure.
The KZ-25 borehole was drilled in an area of leucocratic granite with alkali feldspar syenite layers lying on the basal Li-F granite (Jarchovsky, 2006; Fig.