Formule chimique: Voir BARYTE
Famille: Sulfates
Statut:
Système cristallin : Orthorhombique
Minéral de vitrine: NON
Type d'UV | Couleur principale (*) | Intensité | Fréquence d'observation |
---|---|---|---|
UV longs (365nm): | Blanc bleuté | ||
(*)Vous pouvez ouvrir la charte des couleurs dans une nouvelle fenêtre
Ancien nom pour la barytine fibroradiée trouvée dans les septaria d'Angleterre (voir etiquette) Very different from the Nutfield mineral is the barytes occasionally found in the septaria of the London clay, especially in the Isle of Sheppey. Here it occurs in slender opaque white crystals, arranged in radiating forms or in stellate groups, and rather effectively disposed on the yellow calcite which has crystallised in the contraction-cracks of the nodules, and was formerly called the waxen vein. This occurrence of barytes was recognised by such early observers as Dr. Grew and Sir John Hill, who described the mineral under the name of lepastrum, and appear to have regarded it as gypsum. Some of the specimens here shown (Nos. 1405, 1406) are said to have come from Whitstable Bay ; and according to Sowerby the barytes was also found under similar conditions at Southend, at Sydenham, and at Highgate. (Text from HANDBOOK TO A COLLECTION OF THE MINERALS OF THE BRITISH ISLANDS, . MOSTLY SELECTED FROM THE LUDLAM COLLECTION, IN THE MUSEUM OF PRACTICAL GEOLOGY, JERMYN STREET, LONDON, S.W. , BY F. W. RUDLER, I.S.O., F.G.S. LATE CURATOR OF THE MUSEUM. 1905. )
(*)Les données ne sont pas exhaustives et sont limitées à quelques localités remarquables pour la fluorescence
http://www.mindat.org/show.php?name=Lepastrum
http://webmineral.com/data/Lepastrum.shtml
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