{"title":"Helvine","description":"\u003cp\u003e\u003cstrong\u003eHelvine\u003c\/strong\u003e (also spelled helvite, IMA-approved name helvine) is a beryllium manganese silicate sulfide, Mn4Be3(SiO4)3S, belonging to the \u003cstrong\u003ehelvine group\u003c\/strong\u003e together with iron-dominant \u003cstrong\u003edanalite\u003c\/strong\u003e and zinc-dominant \u003cstrong\u003egenthelvite\u003c\/strong\u003e. Crystallizing in the isometric system with a distinctive hextetrahedral habit, helvine typically forms sharp tetrahedra with a vitreous-to-resinous luster in shades of honey-yellow, orange, greenish yellow, reddish brown and pink; the name itself derives from the Latin \u003cstrong\u003ehelvus\u003c\/strong\u003e, meaning amber, a nod to its classic golden color. It is also notably pyroelectric, generating an electrical charge when heated or cooled, a property it shares with associated quartz. Helvine forms in granites, granite pegmatites, gneisses, and above all in contact-metamorphic skarns, where it appears alongside \u003cstrong\u003egarnet\u003c\/strong\u003e, \u003cstrong\u003emagnetite\u003c\/strong\u003e, \u003cstrong\u003efluorite\u003c\/strong\u003e, \u003cstrong\u003echlorite\u003c\/strong\u003e, \u003cstrong\u003ediopside\u003c\/strong\u003e and \u003cstrong\u003evesuvianite\u003c\/strong\u003e.\u003c\/p\u003e\u003cp\u003eThe classic type localities lie in the \u003cstrong\u003eErzgebirge\u003c\/strong\u003e of Saxony, Germany, at \u003cstrong\u003eSchwarzenberg\u003c\/strong\u003e and \u003cstrong\u003eBreitenbrunn\u003c\/strong\u003e, where historic mines such as the \u003cstrong\u003eBrüder Lorenz Mine\u003c\/strong\u003e yielded the material first described by Freiesleben in the early nineteenth century. Norway is another cornerstone region for the species, with fine crystals from the \u003cstrong\u003eLangesundsfjord\u003c\/strong\u003e, \u003cstrong\u003eHørtekollen\u003c\/strong\u003e, and the amazonite-bearing \u003cstrong\u003eHeftetjern pegmatite\u003c\/strong\u003e in Tørdal, Telemark, alongside syenite pegmatites of the Oslo Rift. Exceptionally large crystals are recorded from \u003cstrong\u003eYxsjö\u003c\/strong\u003e in Örebro, Sweden, while Russia contributes material from the \u003cstrong\u003eIlmen Mountains\u003c\/strong\u003e near Miass in the Southern Urals, and Central Asia offers occurrences at \u003cstrong\u003eKara-Oba\u003c\/strong\u003e, Kazakhstan, and in the \u003cstrong\u003eInylchek Mountains\u003c\/strong\u003e of the Tien Shan, Kyrgyzstan. In the United States, helvine has been collected at Amelia County, Virginia, the American Tunnel near Silverton, Colorado, and Butte, Montana, while important skarn-hosted finds come from Japan's Hongo, Oashi and Yagisawa mines and, more recently, from tin-zinc polymetallic deposits such as Dulong in Yunnan, China. A remarkable modern discovery is the Chingolo skarn mine in Córdoba Province, Argentina, which has produced helvine crystals up to 15 cm along an edge, among the largest known for the species.\u003c\/p\u003e\u003cp\u003eBecause gem-quality faceted stones are exceedingly rare and typically small, helvine is prized chiefly by mineral collectors and skarn\/pegmatite specialists rather than gem cutters, with well-formed tetrahedral crystals on matrix commanding strong interest for their color, crystal habit and relative scarcity. Specimens showing sharp isometric crystal form, good transparency, or transitional chemistry toward danalite or genthelvite are especially sought after, making helvine a rewarding addition alongside phenakite, topaz and beryl for collectors focused on beryllium mineralogy and classic skarn and pegmatite localities worldwide.\u003c\/p\u003e","products":[],"url":"https:\/\/www.italmineral.com\/collections\/helvine.oembed","provider":"ITALMINERAL","version":"1.0","type":"link"}