The fresh water sand sand is solid but easy to nothing without sharp material mix. That may test by bringing the drug sodium hydroxide 3% according to the standard method. MOULUS has a value of between 2.75-3.25 FINESS.
Sand is sand inland a hard edge does not break easily clean any contaminated material, which can be tested with the drug Sodium Hydroxide 3% based on the standard FINESS MOULUS between 2.75-3.25.
The sand is sand freshwater sharp, hard, does not break easily. Clean without other materials, additives, which อาจทดสอบ with the drug, sodium hydroxide 3% along the way. The standard is FINESS MOULUS between 2.75-3.25.