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The minerals that make up Gneiss are almost always: feldspars, quartz, and mica. Sometimes: kyanite, garnet, hornblende, tourmaline, magnetite, and many others.
Source: Geology University Student
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∙ 13y ago
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Which minerals are present in granite but are never present in gabbro?
Never say never, but it's mica.
How do you tell if a rock is worth money?
Quartz rocks are worth money i sold one to a dealer he gave me 35$$.
How do scientists identify minerals?
Scientist identify minerals by Their Special properties. An example of a special propertie is a Chemical Reaction .
Can two igneous rocks be made of the same minerals but have different names?
Yes. The grain texture also matters. For example, basalt and gabbro have the same mineral composition, but basalt, which forms on the surface, has microscopic grains while gabbro, which forms underground, has larger mineral grains.
What intrusive igneous rock is composed of 18 percent olvine 48 percent pyroxene and 34 percent plagioclase?
Gabbro is made of these minerals. The proportions can vary.
Does gabbro have a streak?
Only minerals have a streak, not rocks. The constituent minerals of a gabbro will all have a streak.
What minerals are in granite but not gabbro?
Granite contains Quartz and Plagioclase Feldspar and Gabbro does not have neither if these minerals in it.
How do geologists identify the minerals too small to be seen in a hand specimen?
color streak and luster
What is lighter gabbro or granite?
Granite is lighter because its composed of felsic minerals while gabbro is made up of dark ferromagnesian minerals.
What minerals could you find in a gabbro?
Balls
How do geologists identifying minerals too small to be seen in a hand specimen?
Geologists identify minerals that are too small to be seen in a hand specimen using powerful microscopes. Minerals are classified according to their physical properties such as color, streak, cleavage, hardness and crystal form.
Which minerals are found in basalt and gabbro?
olivine and pyroxene
How identify the coral specimen is hard or soft?
It is difficult or hard to identify a coral specimen
Which minerals are found in the igneous rocks gabbro and basalt?
Olivine and Pyroxene
What makes gabbro a rock and not a mineral?
Gabbro is usually made up of minerals such as pyroxene, plagioclase, amphibole and olivine which makes it an intrusive igneous rock.
Can the minerals which form an intrusive rock also form the same rock but is an extrusive rock?
Yes. For example gabbro and basalt are chemically equivalent (and so are composed of the same minerals), however gabbro is intrusive and basalt is extrusive.
Why would basalt and gabbro generally have higher chemical weathering rates than rhyolite and granite?
The ferromagnesian minerals in the gabbro and basalt are subject to oxidation and chemical breakdown.
