The pure glycine phosphite (pure-GPI) and new β-alanine doped glycine phosphite (β-alanine-GPI) single crystals were grown from slow evaporation and Sankaranarayanan and Ramasamy (SR) method. From the β-alanine doped GPI compound the single crystals were grown. The colourless β-alanine-GPI crystal with cylindrical shape about maximum diameter of 12 mm and length of 25 mm was obtained by this method. The crystalline quality has been analyzed by X-ray diffraction methods. Meyer's index number (n) and vickers hardness value (Hv) of the crystal was calculated from vickers hardness data. The Young's modulus of the β-alanine-GPI crystal was found to be 1.535 x 1010N/m-2 using Knoop microhardness (Hk) measurements. The results of all these characterizations are discussed in detail.