{"product_id":"tourmaline","title":"Tourmaline","description":"\u003cp data-start=\"109\" data-end=\"489\"\u003eBlack tourmaline is a complex borosilicate mineral with a high iron content, giving it its deep black color. It belongs to the tourmaline group, which forms in long, striated crystals and is commonly found in igneous and metamorphic rocks. This mineral is well known for its durability and distinctive crystal structure.\u003c\/p\u003e\n\u003cp data-start=\"491\" data-end=\"500\"\u003eFeatures:\u003c\/p\u003e\n\u003cul data-start=\"502\" data-end=\"1346\"\u003e\n\u003cli data-start=\"502\" data-end=\"627\"\u003e\n\u003cp data-start=\"504\" data-end=\"627\"\u003eComposition: Black tourmaline is a sodium iron aluminum boro-silicate with the general formula NaFe³⁺₃Al₆(BO₃)₃Si₆O₁₈(OH)₄.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli data-start=\"629\" data-end=\"839\"\u003e\n\u003cp data-start=\"631\" data-end=\"839\"\u003eCrystal Habit: Typically forms elongated, vertically striated prismatic crystals, often with a triangular or rounded cross-section. It exhibits no cleavage and breaks with an uneven to subconchoidal fracture.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli data-start=\"841\" data-end=\"972\"\u003e\n\u003cp data-start=\"843\" data-end=\"972\"\u003eFormation: Occurs in granite pegmatites, high-temperature hydrothermal veins, and in metamorphic rocks such as schist and gneiss.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli data-start=\"974\" data-end=\"1182\"\u003e\n\u003cp data-start=\"976\" data-end=\"1182\"\u003ePhysical Properties: Strongly piezoelectric and pyroelectric, meaning it can generate an electrical charge when subjected to pressure or temperature changes—useful in scientific and industrial applications.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli data-start=\"1184\" data-end=\"1346\"\u003e\n\u003cp data-start=\"1186\" data-end=\"1346\"\u003eEducational Value: Ideal for studying silicate mineral groups, crystal systems (hexagonal\/trigonal), and mineral growth in igneous and metamorphic environments.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp data-start=\"1348\" data-end=\"1473\"\u003eThis specimen offers a durable and visually striking example of a common but scientifically significant rock-forming mineral.\u003c\/p\u003e","brand":"The Science Museum of Minnesota","offers":[{"title":"Default Title","offer_id":47750014238934,"sku":"R300","price":3.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0641\/2491\/1830\/files\/black-tourmaline-rough-11024-11024-557110.jpg?v=1769021894","url":"https:\/\/threecrows.com.co\/fr\/products\/tourmaline","provider":"ThreeCrowsLLP","version":"1.0","type":"link"}