Features of Semi-crystalline effect
The phenocrysts in the semi-crystalline structure mostly crystallized underground or during the ascent of magma, and the crystals are relatively coarse. Magma carries phenocrysts up to a lower part of the earth's crust or ejects out of the earth's surface. Unconsolidated magma quickly condenses into a vitreous matrix. At the same time, some crystallites and cryptocrystals can also be formed.