Elements of mineralogy, crystallography and blowpipe analysis from a practical standpoint .. . ot coherent dip a moistened platinumwire in the powder, and treat the adhering powder in the flame. There will be noted both the degree of fusibility and manner offusion. The degree of fusibility is stated in much the same way as thehardness by comparing it with a scale of fusibility. It is gener-ally, however, sufficient to class a mineral as simply easily fusible,fusible, difficultly fusible, or infusible. For purposes of compari-son, the following scale, suggested by v. Kobell, is usuallyadopted:
Elements of mineralogy, crystallography and blowpipe analysis from a practical standpoint .. . ot coherent dip a moistened platinumwire in the powder, and treat the adhering powder in the flame. There will be noted both the degree of fusibility and manner offusion. The degree of fusibility is stated in much the same way as thehardness by comparing it with a scale of fusibility. It is gener-ally, however, sufficient to class a mineral as simply easily fusible,fusible, difficultly fusible, or infusible. For purposes of compari-son, the following scale, suggested by v. Kobell, is usuallyadopted: 1. Stibnitc, coarse splinters fuse in a candle flame. 2. Natrolitc, fine splinters fuse in a candle flame. 3. Garnet [Ahnandite), coarse splinters easily fuse before theblowpipe. 4. Actinolite, coarse splinters fuse less readily before the blow-pipe. 5. Orthoclase, only fused in fine splinters or on thin edges beforethe blowpipe. 6. Calamine, finest edge only rounded in hottest part of flame. 7. Quartz, infusible, retaining the edge in all its sharpness. OPERATIONS OF BLOWPIPE ANALYSIS. 91. The trial should always be made on small and fine pointed frag-ments. Penfield recommends using a standard size about i diameter and 4 mm. long. The fragment should project beyondthe platinum as in Fig. 300, so that heat may not be drawn off ^- 3°°- by the platinum, and the flamedirected especially upon the is always well to examine thesplinter with a magnifying glass,before and after heating, to aidthe eye in determining whetherthe edges have or have not beenrounded by the heat. The manner of fusion may besuch as to result in a glass or slag which is clear and transparent, or white and opaque, or of somecolor, or filled with bubbles. There may be a frothing or intu-mescence, or a swelling and splitting (exfoliation). In certain in-stances the color and form may change without fusion, etc. Flame Coloration. During the fusion test the non-luminous veil is sometimes un-changed
Size: 1792px × 1394px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1900, bookpublishernewyorkdvannostran
