https://www.cfloworld.com/solutions/industries-we-serve/foundry-sand/
Foundry sand (also known as Casting Sand) consists primarily of clean, uniformly sized, high-quality silica sand that is bonded to form moulds for ferrous (iron and steel) and nonferrous (copper, aluminium, brass) metal castings.
https://cfloworld.com/solutions/industries-we-serve/manufactured-sand-technology/
Manufactured sand (M-Sand) is artificial sand produced from crushing hard stones into small sand sized angular shaped particles, washed and finely graded to be used as construction aggregate. It is a superior alternative to River Sand for construction purpose.