Classification of granites |
Hoyt, unfortunately, fell victim to Demand Media's minimum word count specification. He started out by introducing his topic and explaining the difference between the two:
"Quartz monzonite... and granite are both granitic rocks... that bear a superficial resemblance to one another... Quartz monzonite contains 5 to 20 percent quartz. Granite contains 20 to 60 percent quartz."
"Granitic rocks are igneous, meaning they were formed by heat under the crust of the earth."Actually, "igneous" means that that a rock crystallized from a melt, generally within the crust instead of under it. Hoyt had some other goofs in his padding, including
- "Agates are a form of quartz crystals." – Agate is microcrystalline Si02, so not "a form of quartz crystals"
- "...quartz monzonite contains K-feldspar, which is similar to quartz..." – No, orthoclase is not "similar to quartz."
- "Some 60 percent of the earth's outer crust is made of feldspar that consists of aluminum silicates plus calcium, potassium, sodium and sometimes barium.." – "Outer" crust? The crust is the outer layer... and barium feldspars are pretty darned rare.
- "Stone Mountain, Georgia, is made of quartz monzonite..." – A geologist wouldn't say it's "made" of quartz monzonite but that it's composed of it.
¹ A staffer recognized Hoyt's name and allowed as to how much she's liked his Richard Denson novels...
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SI - PETROLOGY
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