Abstract: A cross-contamination free and multiple laboratory sample grinder is disclosed which includes: a controller unit having a motor and a controller unit; a tube receptacle unit, removably laid on top of the controller unit, comprising a plurality of compartments designed to contain a plurality of laboratory tubes; and a top housing unit, removably laid on top of the tube receptacle unit, comprising an array of pestles coupled to a gear system operated by that motor, wherein the top housing unit comprises a handle when rotated operable to eject the array of pestles into said plurality of laboratory tubes.