Uvite Tourmaline Crystal Mineral Specimen
HISTORY, NAME, LOCALITIES: Uvite, pronounced YOU-vite, was recognized as a mineral species in 1929 and named for its discovery location in Uva Province in Sri Lanka (formerly Ceylon). Uvite is collected in Brazil, Pakistan, Madagascar, Namibia, Sri Lanka, Myanmar, Canada, Mexico, and the United States (New York, Arkansas, Colorado, New Hampshire).
MINERALOGY, PROPERTIES, OCCURRENCE: Uvite [basic calcium magnesium aluminum oxyborosilicate, CaMg3Al6(BO3)3(Si6O18)(OH)3O] is an uncommon, calcium-magnesium-rich member of the tourmaline group and crystallizes in the hexagonal system (trigonal subsystem) as stubby, striated prisms with hexagonal cross sections. It is transparent to nearly opaque, has a vitreous luster, lengthwise striations, and is usually black, greenish-black, brownish-black, or dark green. It has a substantial Mohs hardness of 7.0-7.5, no cleavage, and a specific gravity of 2.9-3.2. Uvite occurs primarily in calcium- and boron-rich, metamorphic and skarn-type environments. In 2011, mineralogists employed advanced quantitative-analytical methods to redefine uvite as two separate minerals that are end-members of a solid-solution series: Uvite now refers to the hydroxyl-dominant end-member, while fluor-uvite is the correct name for the fluorine-dominant end-member.
METAPHYSICAL PROPERTIES, LORE, USES: Modern metaphysical practitioners believe that uvite diminishes fears and promotes self-confidence, awakens one from illusions, brings an awareness of reality, and enhances fortitude. Uvite has neither technological nor jewelry uses.
COLLECTORS’ INFORMATION: Uvite is collected because of its rarity and frequent association in attractive composite specimens with such minerals as quartz, muscovite, and apatite-(CaF).
CORUNDUM (var. SAPPHIRE)
HISTORY, NAME, LOCALITIES: The sapphire variety of corundum has been collected since antiquity. The name “corundum,” pronounced coh-RUN-dum, stems from kuruvinda, the ancient Sanskrit word for “ruby”; the word “sapphire,” pronounced SAH-fire, comes from the Latin sapphirus, meaning “blue” and referring to the classic sapphire color. Sapphire is collected in Myanmar, Tanzania, Sri Lanka, Thailand, Cambodia, India, Malawi, and the United States (Montana).
MINERALOGY, PROPERTIES, OCCURRENCE: Corundum [aluminum oxide, Al2O3] crystallizes in the hexagonal system as tapering or pyramidal prismatic crystals in rough and rounded barrel shapes, and as granular masses. It has a Mohs hardness of 9.0, no cleavage, and a specific gravity of 3.9-4.1. Corundum is transparent to translucent and occurs in all colors. The red gem variety is ruby; all other colors are sapphire. The classic blue color of sapphire is due to iron and titanium chromophores. Sapphire occurs in nepheline-syenite pegmatites, metamorphic rocks, and secondary alluvial deposits.
METAPHYSICAL PROPERTIES, LORE, USES: Sapphire, one of the first precious gemstones ever mined, is the birthstone for September. Metaphysical practitioners believe that sapphire is a stone of wisdom and learning that enhances the ability to see underlying truths, helps to access deeper levels of consciousness, and promotes order, structure, and discipline. Non-gem-quality sapphire crystals were once fashioned into jewel bearings for fine watch movements. Transparent blue sapphire, one of the classic precious gemstones, is faceted into very costly gems; translucent star sapphire is fashioned into cabochons.
COLLECTORS’ INFORMATION: Sapphire specimens are collected for their rarity, color, and interesting crystal habits.
HISTORY, NAME, LOCALITIES: Muscovite has been known since antiquity when it was called “white mica” and used in powdered form to whiten paints. In 1850, it was assigned its name, which stems from the Russian principality of Muscovia (Moscow), where thin sheets called “isinglass” were used as a substitute for glass in windows and ovens. Notable collecting localities are found in Namibia, Russia, Brazil, Pakistan, Malawi, Austria, Madagascar, and the United States (Maine, Vermont, South Dakota, Colorado, New Mexico, California, Virginia).
MINERALOGY, PROPERTIES, OCCURRENCE: Muscovite [basic potassium aluminum silicate, KAl2ALSi3O10(OH)2], pronounced MUSS-coh-vite, crystallizes in the monoclinic system as thin, tough, elastic, sheet-like crystals aligned parallel to its perfect, one directional cleavage. Muscovite is a phyllosilicate mineral with a Mohs hardness of 2.0-2.5, vitreous-to-pearly luster, specific gravity of 2.7-3.0, and tendency to form aggregates of well-developed crystals called “mica books.” Muscovite cleaves easily into thin, semi-transparent, silvery-white sheets. As an abundant rock-forming mineral, muscovite is an essential component of many igneous, metamorphic, and sedimentary rocks and achieves its best crystal development in granite pegmatites.
METAPHYSICAL PROPERTIES; LORE, USES: Metaphysical practitioners believe that muscovite aids problem solving, stimulates quickwittedness, and alleviates anger, stress, and self-doubt. Because of its low coefficients of friction and thermal expansion, inertness, and excellent heat- and electrical-insulating properties, muscovite has many uses in industry and is mined extensively.
COLLECTING INFORMATION: Muscovite is collected for its unusual crystal forms, usually as composite specimens in association with such pegmatite minerals as beryl, quartz, and microcline.