Dimension stone not only represents the quality, including strength, color, and polish indexes but also shows the size and shape to obtain standard requirements for the processing plant. One of the issues affecting the size and block recovery ratio is discontinuities inside the stone, dividing into specific sizes and shapes. Therefore, the paper shows a relationship among three main joint sets, existing in the quarries, influencing the size and shape of a stone block generated by intersections of these joint sets. Each joint set is characterized by dip, dip direction, and spacings. Modelling discontinuities from three main joint sets generated a stone block with a specific size and shape. The paper carried out at stone quarries in Phu Yen, Binh Dinh, and Khanh Hoa Provinces. The results showed that when changing one of the geometry parameters of these joint sets, the size, and shape will be correspondingly changed. These sizes and shapes depend on the spatial intersection of these joint sets. In addition, the recovery ratio of each block for processing was calculated regarding its shape to assess which quarries have a good relationship with joint sets. From the minimum size for the processing plant is a rectangular parallelepiped of 0.4 m3, the minimum spacing of joints in a set was defined to satisfy such requirements. This contributes to showing which quarries have a favorable condition on stone size and shape the plant requires. From this, the spacings are equal or more than the minimum spacing in each joint set for quarries determined to calculate the reverse of the rectangular parallelepiped of equal or more than 0.4 m3.