What’s the difference between sea garnet sand and rock garnet sand?

The basic difference is in the microscopic shape. Rock garnet has edgy shapes and sea garnet has round shape.

India garnet sand is river garnet sand, is cleaner than rock garnet sand, China garnet sand is rock garnet sand, rock garnet sand has a higher hardness than river garnet sand. So we can say, the river garnet sand is suitable for water jet cutting, the rock garnet sand is more suitable for sandblasting. Besides, garnet sand 30/60 mesh 20/40 mesh are the normal sizes for sandblasting.
India river garnet sand is pink color, China rock garnet sand is deep red color.
India river garnet sand is expensive than China river garnet sand.