Willemite


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willemite

[′wil·ə‚mīt]
(mineralogy)
Zn2SiO4 A white, greenish-yellow, green, reddish, or brown mineral that forms rhombohedral crystals and exhibits intense bright-yellow fluorescence in ultraviolet light; a minor ore of zinc.

Willemite

 

(after King Willem I of the Netherlands), a mineral, Zn2SiO4 (73.0 percent ZnO, 27.0 percent SiO2). Admixtures of Mn2+ are common. Crystallizes in a trigonal system. The structure is complex, composed of tetrahedrons of SiO4 and ZnO4 linked by common oxygens. Prismatic or acicular crystals are rare; they are usually granular or radial-fibrous aggregates, incrustations, and so on.

Willemite is colorless, greenish, or yellowish brown, and it phosphoresces brightly in ultraviolet light or cathode rays. Hardness on the mineralogical scale, 5-6; density, 3,890-4,180 kg/m3. It formed both in oxidation zones of lead-zinc deposits and in certain contact-metasomatic deposits (at Franklin in the USA). It is used as a zinc ore. It is also used to make fluorescent screens in cathode-ray tubes and other instruments.

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Penarth switched off soon after, allowing Bath to gain in confidence and hit back to 3-2 before Willemite made it 4-2 at the break.
Penarth's senior side drew 2-2 with Whitchurch, thanks to goals from David Joyce and Andrew Willemite, while the 3rd XI began their pre-season preparations with a fixture against a Cardiff Medics team set to compete two divisions higher, going down 4-3 with goals from James Kidby (2) and Dave Watkins.
2132 Willemite and Franklinite, Franklin, New Jersey, no.
A zone was found surrounding an area to the north, near the modern entrance to the Red Cloud mine, containing fluorescent minerals similar to some of those found at Franklin, New Jersey, including red-fluorescing calcite and green-fluorescing willemite.
Willemite is rarely found in well-formed, translucent to transparent crystals.
Finally, there was the "Fluorescent Tent": a 15 X 25 foot-long tent which contained hundreds of Franklin-Ogdensburg ore specimens of willemite, calcite, esperite and many other rarities carefully selected for their unique combination of patterns and associations.
dollars, 1987-1992) of the gem materials; the other lists 28 "non-traditional gemstones," amblygonite to willemite, with generous mineralogical, optical and geological/genetic data.
Willemite and hemimorphite came to be mined as ores (the lustrous white hemimorphite specimens known as "maggot ore" began to emerge around 1875 from the opencut Noble and Passaic workings at Sterling Hill).
Vein Minerals Adamite Goethite Arsenopyrite Gold Austinite Hemimorphite Barite Malachite Beudantite Mimetite Calcite Smithsonite Cerussite Sphalerite Chalcopyrite Plumbojarosite Chlorargyrite Pyrite Chrysocolla Rosasite Conichalcite Tetrahedrite Fluorite Willemite Galena Wulfenite
Allan Young's case of 35 impeccably tasteful thumbnails from Idaho localities, many of them self-collected, was noteworthy, as was Tom Hughes' case which was entirely filled with self-collected things, including a wide, beautiful, baby-blue Silver Bill mine, Arizona rosasite and a terrific thumbnail of willemite ("troostite") from the Sterling Hill mine, New Jersey.
Descloizite was typically found in close association with vanadinite and wulfenite, and more rarely with calcite and willemite near the borders of the orebody.