Here is an impressive Ametrine gem! It is one of the largest gemstones we have and it has been concave cut into this fantastic long emerald shape. The orientation of color is excellent, spliting the purple and yellow bi-color to give the stone a classic appearance. Ametrine is a naturally occurring purple and yellow bi-color variety of Quartz that is formed by a unique twin law ("Brazil Law Twinning") where two separate individually colored crystals are intergrown to form an alternating "radiation" pattern of purple (Amethyst) and yellow (Citrine) triangles when viewed down the c axis. The two colors are oriented based upon their position inside the crystal to create the famous bicolor gemstones. This stone has been concave cut to produce that lovely radiant pattern of the flash. This is a top notch Ametrine and is a fabulous collector’s gemstone. Enjoy!