Silica is found in the upper mantle but not granite.
Is most of the upper mantle made of granite.
Most of the minerals in the mantle are silicates meaning they contain silica.
The cooler mantle material will there fore tend to sink while the hooter material will tend to rise.
Rapid cooling of magma or lava results in rocks with small interconnected mineral grains.
Although most upper mantle rocks can be assumed to be peridotite mostly made of olivine and pyroxene other minerals including oxides and hydrates should be taken into account especially when they participate in transitions or chemical reactions that may affect the physical properties of the mantle rocks.
Much of upper mantle is thought to be made of granite.
A glassy texture is the result of lava that has cooled very slowly.
Around the core is the mantle which is the thickest of the layers.
The upper mantle of the earth is a very thick layer of rock inside the planet which begins just beneath the crust at about 10 km 6 2 mi under the oceans and about 35 km 22 mi under the continents and ends at the top of the lower mantle at 670 km 420 mi.
It is liquid rock that keeps the earth s outermost layer the crust floating and moving across the surface of our world.