What is the streak of plagioclase?
What is the streak of plagioclase?
| Physical Properties of Plagioclase | |
|---|---|
| Chemical Classification | Silicate |
| Color | Usually white or gray. Also colorless, yellow, orange, pink, red, brown, black, blue, green. |
| Streak | White |
| Luster | Vitreous. Pearly on some cleavage faces. |
Which is a fine grained igneous rock made up primarily of pyroxene and plagioclase feldspar?
LARGE LARGEI 4. Which is a fine-grained igneous rock made up primarily of pyroxene and plagioclase feldspar? 2) basalt (4) rhyolite .
What is the streak of an igneous rock?
Streak: The streak of a mineral is the color of its powder left behind when rubbing it against a hard surface like a porcelain tile. Luster is the term used to describe how light is reflected from a mineral’s surface. Nonmetallic is divided into glasslike or dull. like it should, they have an average density.
What igneous rocks are fine grained?
Basalt is a fine-grained mafic igneous rock. It is commonly vesicular and aphanitic. When porphyritic, it often has either olivine or plagioclase phenocrysts.
What are the physical properties of plagioclase feldspars?
Physical Properties of Plagioclase Minerals. These properties make plagioclase feldspars relatively easy to identify with a hand lens in coarse-grained igneous and metamorphic rocks. Plagioclase in granitic rocks is normally white, pink, or red in color. In basaltic rocks it is normally gray to black.
Where are plagioclase minerals found in the earths crust?
Geologic Occurrence of Plagioclase Members of the plagioclase group are the most common rock-forming minerals. They are important to dominant minerals in most igneous rocks of the Earth’s crust. They are major constituents in a wide range of intrusive and extrusive igneous rocks including granite, diorite, gabbro, rhyolite, andesite, and basalt.
What makes up most of the feldspar in granite?
Granite is a plutonic rock in which quartz makes up between 10 and 50 percent of the felsic components. Alkali feldspar accounts for 65 to 90 percent of the total feldspar content. Applying this definition requires the mineral identification and quantification abilities of a competent geologist.
What are the colors of plagioclase in basaltic rocks?
Plagioclase in granitic rocks is normally white, pink, or red in color. In basaltic rocks it is normally gray to black. Oligoclase: A cleavage fragment of oligoclase. This specimen is from Mitchell County, North Carolina.