Q 01/05

Which of these is the main type of rock that granite belongs to?

A) Metamorphic

B) Intrusive igneous

C) Sedimentary

D) Extrusive igneous

Answer · why

B) Intrusive igneous

It crystallises slowly from silica-rich magma underground, which is why its individual grains are large enough to see.

Q 02/05

The word "granite" comes from the Latin granum, meaning what?

A) A mountain

B) A grain

C) A stone

D) A spark

Answer · why

B) A grain

The name refers to the coarse, completely crystalline texture that you can see with the naked eye.

Q 03/05

Which of these minerals is NOT one of granite's main ingredients?

A) Mica

B) Feldspar

C) Quartz

D) Calcite

Answer · why

D) Calcite

Calcite is the stuff of limestone and marble; granite is built from quartz, feldspars and mica or amphibole.

Q 04/05

By modern convention, true granite contains what proportion of quartz by volume?

A) Over 90%

B) 5% to 15%

C) 20% to 60%

D) 65% to 80%

Answer · why

C) 20% to 60%

Rocks with more than 60% quartz are simply called quartz-rich granitoids, and those with almost nothing else are quartzolite.

Q 05/05

What is the extrusive (volcanic) equivalent of granite?

A) Rhyolite

B) Obsidian

C) Andesite

D) Basalt

Answer · why

A) Rhyolite

Same chemistry, but erupted and cooled fast at the surface, so the crystals stay tiny.