First, the sand must undergo heat and pressure deep beneath the Earth's surface, causing the sand grains to recrystallize and fuse together. This transforms the sedimentary rock into metamorphic rock.
The processes involved in the formation of metamorphic rock from sand are compaction and cementation, which lead to the formation of sandstone, and then the transformation through heat and pressure, which results in the metamorphism of sandstone into metamorphic rock.
