{"title":"Sapphire","description":"\u003cp\u003e\u003cstrong\u003eSapphire\u003c\/strong\u003e is the gem-quality blue variety of \u003cstrong\u003ecorundum\u003c\/strong\u003e, an aluminum oxide (Al2O3) prized for exceptional hardness (9 on the Mohs scale, second only to diamond) and superb brilliance. While the classic hue is a rich cornflower to royal blue, sapphire also occurs in yellow, green, violet, colorless (\"leucosapphire\") and the delicate pinkish-orange padparadscha; only red corundum is called ruby instead. Trace elements govern the color: iron and titanium produce blue through intervalence charge transfer, while iron alone yields yellows and greens. Some crystals display asterism, forming star sapphires when oriented needles of rutile silk reflect light into a six-rayed star across a cabochon.\u003c\/p\u003e\u003cp\u003eThe most legendary source is Kashmir, where crystals recovered from the Paddar Valley of the Zanskar Range since an 1881 landslide display a velvety, sleepy blue prized above all other origins, though the historic deposits are now largely exhausted. Myanmar's Mogok Stone Tract, the Mong Hsu deposit, and Sri Lanka's Ratnapura, Bibile and Rakwana gem gravels have long supplied the finest large, clean crystals, with Sri Lanka remaining the classic source of oversized faceted stones. In the United States, Montana is the benchmark locality: the igneous Yogo dike near Lewistown produces uniquely uniform cornflower-blue sapphire directly from bedrock, while alluvial gravels at Rock Creek, Dry Cottonwood Creek and along the Missouri River near Helena yield the fancy-colored \"Montana sapphires\" collectors seek for their natural, unheated palette. Other important localities include Pailin in Cambodia, the Chanthaburi district of Thailand, Ilakaka and Andranondambo in Madagascar, the Umba Valley and Tunduru district of Tanzania, Australia's New South Wales and Queensland basalt fields, Vietnam's Luc Yen, Nigeria, and Kashmir's neighboring Hunza Valley in Pakistan.\u003c\/p\u003e\u003cp\u003eCollectors and gemologists value sapphire specimens not only for color and clarity but for locality-diagnostic inclusions: silk, rutile needles, zircon halos, and mineral inclusions such as apatite, spinel or biotite mica help distinguish Kashmir, Sri Lankan, Burmese and Malawi material from one another. Well-formed hexagonal barrel- or bipyramid-shaped crystals, twinned lamellae, and richly saturated gem rough from these historic mines remain highly sought after for both mineralogical study and fine jewelry, making sapphire one of the most enduringly collected and commercially important gem species in the world.\u003c\/p\u003e","products":[],"url":"https:\/\/www.italmineral.com\/collections\/sapphire.oembed","provider":"ITALMINERAL","version":"1.0","type":"link"}