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Alkali feldspar has the general formula (K,Na)AlSi3O8, but varies in crystal structure depending on the temperature it formed at. The formula actually is a blend ranging from all sodium (albite) to all potassium (microcline), but albite is also one endpoint in the plagioclase series so we classify albite there.
This mineral is often called potassium feldspar or K-feldspar, because by definition potassium always exceeds sodium in its formula. It comes in three different crystal structures that depend on the temperature it formed at.
Microcline is the stable form below about 400° C. Orthoclase is stable above 500° C and sanidine is stable above 900° C. In a plutonic rock that cooled very slowly to yield large mineral grains, it's safe to assume that this is microcline.
In the field, workers generally just write down "K-spar" and leave it at that until they can get to the laboratory. Alkali feldspar is generally white, buff or reddish and is not transparent, nor does it show the striations of plagioclase. A green feldspar is always microcline, the variety called amazonite.
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Is feldspar a compound or mixture?
Feldspar is a mixture.
Which is the most abundant feldspar mica quartz calcite?
Feldspar is the most abundant mineral in the earth crust.
Which object can scratch apatite but not feldspar?
Glass can scratch apatite but not feldspar.
Which object can scratch feldspar but not quartz?
steel file 6.5
What are some coordinates of green feldspar?
write the correct coordinates of green feldspar
What are the uses of microline?
Microline is a mineral that has been used as a semi-precious stone. It has been called Perthite and Amazonite. Microline is used in making porcelain.
Is feldspar dark colored?
Feldspar is a group of common, rock-forming minerals with 19 member species. These minerals are mostly colorless, white, off-white, light brown or gray, but one can find almost any color among the feldspar members. Certain potassium-rich feldspars may be a salmon to pink color. A certain variety of the mineral microcline called amazonite is turquoise to greenish blue. A certain variety of the mineral anorthite called labradorite is nearly black with a dark blue, green, red and gold sheen or iridescence (schiller). The well-known moonstone is another variety of some of the feldspar minerals with its pale to creamy color and iridescence. Sunstone is a peach-colored variety of the mineral albite that has a similar luster.
Is feldspar metalic?
no, feldspar is a mineral.
Is feldspar a metal?
no, feldspar is a mineral.
Is feldspar a compound or mixture?
Feldspar is a mixture.
What is the fracture of feldspar?
Feldspar's fracture is brittle
What feldspar fracture?
The fracture of feldspar is conchoidal or brittle.
What is feldspar fracture?
The fracture of feldspar is conchoidal or brittle.
Step like cleavage is a property of what mineral?
feldspar
What minerals is a silicate Gematite Feldspar Calcite Halite?
Feldspar
What is the feldspar?
Feldspar is a mineral found prety mutch anywhere.
What has feldspar in it?
Feldspar can be found in many things, including soap
