The crystal L-threonine grown by slow evaporation technique at various pH has been subjected to micro-hardness studies and chemical etching. The Meyer's index (n), yield strength (σ v), and elastic stiffness constant (c 11) were calculated using Vicker's micro- hardness number.Microhardness studies revealed that the hardness of the grown crystal increases with an increase in load. From Meyer's index number it was found that material belongs to soft material category. It has been observed that L-threonine at isoelectric pH shows good mechanical strength. The Young's modulus has been estimated by Knoop's micro-hardness number. The surface of the grown crystals can be analyzed by chemical etching using water and methanol as an etchant. The results have been discussed in detail.