VSI Dust, also known as Crusher Dust or Quarry Dust, is a by-product of the crushing process of rock or stone in VSI (Vertical Shaft Impactor) machines. It typically ranges from fine dust particles to a maximum size of 4.75mm with a specific gravity ranging from 2.6 to 2.9 .Doctor Sand offers top quality VSI dust, used in mortars for bricklaying and concrete applications .