What color is potassium feldspar streak?
What color is potassium feldspar streak?
Potassium Feldspar
| Type | Mineral |
|---|---|
| Hardness | 6 > Glass |
| Cleavage | Yes Prismatic at right angles |
| Streak | None |
| Color | Pink or White |
Is potassium feldspar always pink?
Alkali feldspar (also called potassium feldspar or K-feldspar) has a color range from white to brick-red, and it’s typically opaque.
How do you identify potassium feldspar?
In general, keys to identifying K-feldspar are its (lack of) color, its low birefringence, and its twinning. In thin section, microcline, orthoclase and sanidine are distinguished by their twinning, optical sign, and 2Vo.
Why is potassium feldspar pink?
K–feldspar albite intergrowths known as pertite and albite intergrowths K–feldspar as antipertite. The hardness is from 6 to 6.5 and the relative density of 2.55–2.63. The color is usually white, and sometimes changes from pale pink to reddish due to admixtures of iron (especially microcline).
What is the colour of feldspar?
As indicated by the fact that they lack inherent colour, feldspars can be colourless, white, or nearly any colour if impure. In general, however, orthoclase and microcline have a reddish tinge that ranges from a pale, fleshlike pink to brick-red, whereas typical rock-forming plagioclases are white to dark gray.
What mineral has a white streak?
fluorite
Other minerals leave surprising colors, such as fluorite, which always has a white streak, although it can appear in purple, blue, yellow, or green crystals.
Is potassium feldspar mafic or felsic?
Image Descriptions
| Igneous Rocks | Felsic | Mafic |
|---|---|---|
| K-feldspar | 0 to 35% | 0% |
| Quartz | 25 to 35% | 0% |
| Plagioclase feldspar | 25 to 50% | 0 to 50% |
| Biotite and/or Amphibole | 0 to 20% | 0 to 30% |
Can feldspar be yellow?
Pale yellow color in feldspar is due to Fe3+ in the tetrahderal Si/Al site. This color is often masked by the pervasive turbidity of common feldspars. Smoky color, the result of radiation damage from the decay of potassium-40, is also common but often masked.
Can feldspar be blue?
Lead-containing feldspars with a higher degree of Al/Si disorder (typically orthoclase) are green where more the more common ordered feldspars (microcline) become blue from irradiation. Feldspars with intermediate ordering often show both a green and a blue component in the spectrum.
What is another name for potassium feldspar?
Amazonite (sometimes called “Amazon stone”), a green variety of microcline.
What mineral has a red streak?
Hematite
Hematite (top right), realgar, erythrite and cinnabar are minerals with a red streak.
Is potassium feldspar intrusive or extrusive?
An example of such a mosaic is granite, a coarse-grained, intrusive rock containing potassium feldspar, quartz, plagioclase feldspar, and small amounts of biotite and hornblende.