190 Carat Ametrine Facet Rough Purple Orange Amethyst and Citrine Natural Quartz Crystal Mineral Gemstone - Brazil You will receive exactly this Ametrine Rough - 37mm x 30mm x 23mm / 1 7/16 x 1 3/16 x 15/16 Inches; 38g / 1.3 oz / 190 Carat (see photo, the photos are taken under bright light, some photos are taken wet, stand not included)! Ametrine is among an elite group of gems, because as of now there is just one source of this treasure in the world. According to legend, the Ayoreo Indian tribe of eastern Bolivia knew about the bicolor quartz crystals over 500 years ago. Perhaps the earliest formal documentation of natural quartz crystals with zonal coloring of purple and yellow is in a 1925 issue of American Mineralogist. These were basal sections of quartz crystals with color sectors alternating between purple and yellow. Amethyst: a violet to purple variety of quartz. Formula: SiO2; Colour: Violet - Purple; Citrine: chemical Formula: SiO2; Composition: Silicon dioxide; Hardness: 7; Color Yellow, yellow-brown, orange, dark orange-brown, reddish-brown; The words AMEthyst and ciTRINE were combined to yield the name "ametrine," which is widely used in the gemstone trade. Ametrine is rarely found in nature. Ametrine is a rare gemstone with a finite supply that is produced in commercial quantities at only one mine in the world. It is a relative newcomer to the gemstone trade, being available in small quantities for just a few decades. Ametrine is a variety of bicolor quartz that has zones of amethyst (purple) and citrine (golden yellow) in contact with one another in a single crystal. (The above information is provided solely for informational purpose. Kindly note that all stones are offered for decorative purposes only. Please, handle your stones with great care, do not grind or crumble them, do not dip or add them into your food or drink, do not use any parts of them in any elixirs, potions, lotions etc. Always make sure you wash your hands before and after working with your crystals.)