All our minerals and crystals are carefully measured with digital measuring instruments that provide the high accuracy of numbers/values!

• Tourmaline is not a single mineral, but a group of several closely related minerals. The three most well-known members are Elbaite, Schorl, and Dravite. Other lesser known members include Uvite, Liddicoatite and Buergerite. Tourmaline is a crystalline boron silicate mineral compounded with elements such as aluminium, iron, magnesium, sodium, lithium, or potassium. Tourmaline is classified as a semi-precious stone and the gemstone comes in a wide variety of colors.
• Chemical Composition: (Na, Li,Ca) (Fe2, Mg, Mn, Al)3 Al6 I(OH)4 I (BO3)3ISi6O18I; Color: Most commonly black; Mohs scale hardness: 7-7.5;
• In its natural state, all the Tourmalines are characterized by parallel ridges (striations) which run the length of the crystal, as are the Black Tourmalines which are the most common in the Tourmaline group. Tourmaline forms in igneous and metamorphic rocks and veins. It frequently occurs with Lepidolite, Microcline, and Spodumene in granite pegmatites and others.
• (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.)
• You will receive exactly this Green Tourmaline Cluster - 65mm x 48mm x 40mm / 2 9/16 x 1 7/8 x 1 9/16 Inches; 150g / 5.3 oz / 750 Carat (see photo, stand not included, some photos are taken wet)!In additional, you will get one of the Mahogany Obsidian Cabochon similar to the one in the listing, the size and the color of the cabochon may slightly vary as well due to the fact that all minerals are different.Approximately Size: 10-30mm / 7/16-1 3/16 Inches;Approximately Weight: 15-40gr / 0.5-1.4oz.

Tourmaline is not a single mineral, but a group of several closely related minerals. The three most well-known members are Elbaite, Schorl, and Dravite. Other lesser known members include Uvite, Liddicoatite and Buergerite. Tourmaline is a crystalline boron silicate mineral compounded with elements such as aluminium, iron, magnesium, sodium, lithium, or potassium. Tourmaline is classified as a semi-precious stone and the gemstone comes in a wide variety of colors.HQRP-Crystal