. Precious stones, a popular account of their characters, occurrence and applications, with an introduction to their determination, for mineralogists, lapidaries, jewellers, etc. With an appendix on pearls and coral. Precious stones; Pearls; Corals. EPIDOTE 417 EPIDOTE. Epidote is another mineral which is used as a gem only occasionally when of specially fine quality. Almost the only locality at which transparent, finely-coloured crystals of gem- quality are to be found is the Knappenwand in the uppermost part of the Untersulzbachthal, in Pinzgau, Salzbm-g. There are many other localities, but
. Precious stones, a popular account of their characters, occurrence and applications, with an introduction to their determination, for mineralogists, lapidaries, jewellers, etc. With an appendix on pearls and coral. Precious stones; Pearls; Corals. EPIDOTE 417 EPIDOTE. Epidote is another mineral which is used as a gem only occasionally when of specially fine quality. Almost the only locality at which transparent, finely-coloured crystals of gem- quality are to be found is the Knappenwand in the uppermost part of the Untersulzbachthal, in Pinzgau, Salzbm-g. There are many other localities, but they seldom yield stones which are sufficiently transparent and finely colom-ed for use as gems. The chemical composition of epidote is expressed by the formula: (Al,Fe) The mineral is thus a hydrous silicate of calcium and aluminium, in which a variable proportion of the aluminium is replaced by ferric iron. An analysis of epidote from the Knappenwand is given below: Per cent. Silica (SiOa) .... ... 37-83 Alumina (AljOg) 22-63 Ferric oxide (FegOs) 14-02 Ferrous oxide (FeO) 0-93 Lime (CaO) 23-27 Water 2-05 100-73 Crystals of epidote are of very frequent occurrence. They belong to the monoclinic system and are usually prismatic in habit, the direction of elongation being parallel to the. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Bauer, Max, 1844-1917; Spencer, Leonard James, 1870- tr. London, C. Griffin and Company, Ltd.
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