. The prospector's field-book and guide in the search for and the easy determination of ores and other useful minerals. EXAMINING A GEM THROUGH THE DICHROISCOPE. stones of various shades and colors has been ac-quired. The diehroiscope is in the shape of a cylin- Fig. When a transparent or semi-transparent stone is examined through thediehroiscope, the color of the square A is different or of a different shade tothat of the square B when dichroism exists. der 2 inches long and 1 inch in diameter, and thuseasily carried Placing by means of tweezers a translucent ortransparent stone
. The prospector's field-book and guide in the search for and the easy determination of ores and other useful minerals. EXAMINING A GEM THROUGH THE DICHROISCOPE. stones of various shades and colors has been ac-quired. The diehroiscope is in the shape of a cylin- Fig. When a transparent or semi-transparent stone is examined through thediehroiscope, the color of the square A is different or of a different shade tothat of the square B when dichroism exists. der 2 inches long and 1 inch in diameter, and thuseasily carried Placing by means of tweezers a translucent ortransparent stone close to the one end of the instru- GEMS AND PRECIOUS STONES. 269 ment where the two square images are seen whenthe instrument, held skywards, is looked into, andturning it about in various directions, and at thesame time turning the instrument round, the ob-server will notice whether the color of the twosquares is one and the same. If the stone is amor-phous, such as flint, obsidian, etc., or crystallizingaccording to the cubic system, such as diamond,spinel ruby, garnet, etc., the two squares will be ofthe same color to that of the other when the coloredstone is examined in certain directions, though itmay be the same in certain others. Thus a true ruby, which a
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectprospec, bookyear1903
