Unlike diamonds, most colour gemstones are variegated and exhibit pleochroism. Cutting styles and orientation for colour gemstones is thus the most influential factor controlling the face up appearance of the gemstones. With the advancement of faceting machines precision cutting and concave cutting are now becoming viable. The research will bring us an insight of "ideal cut" for various gemstones not just optimising the brilliance but also the best colour. In addition it will give an idea on we can achieve colour grading of gemstones with various shapes.