What is it and where is it formed?
Gneiss is a
rock that has streaks of
minerals through it.
Most of the time, it has feldspar,
mica in it.
It is named for the mineral that’s in it the most. An
example of this is garnet gneiss which has mostly garnet in
it. It doesn’t mean that is the only mineral in it—just the
highest amount. It is formed in
igneous, but most often
metamorphic rocks. Gneiss is formed when there is a lot of
pressure and heat and the rocks melt.
How and where is it mined?
Gneiss are mined using
underground mining. It is found all
over the world but mostly in mountain ranges like the
Adirondacks and the Rocky Mountains.
What is it used for?
Gneiss is used in
buildings, roads, and curbs.
It is pronounced like “nice”.
If you have a
piece of gneiss, the light layers going through it are quartz and feldspar. The dark layers are
hornblende and biotite mica.