 | James Dwight Dana - 1844 - 660 lapas
...variety. 7. Quartz; transparent. 8. Topaz: transparent. 9. Sapphire; cleavable varieties. 10. Diamond. * If the file abrades the mineral under trial with the...facility than 4, but less than 5, the hardness may be 4J or 4J, written in decimals 4.25, 4.5. Several successive trials should be made to obtain certain... | |
 | James Dwight Dana - 1850 - 800 lapas
...variety. 7. Quartz ; transparent. 8. Topaz ; transparent. 9. Sapphire ; cleavable varieties. 10. Diamond. If the file abrades the mineral under trial with the...facility than 4, but less than 5, the hardness may be 4j or 4^, written in decimals 4-25, 4-5. Several successive trials should be made to obtain certain... | |
 | James Dwight Dana - 1854 - 946 lapas
...cleavable varieties. 10. L)nimond. If the file abrades the mineral under trial with the same ease as У >. 4. and produces an equal depth of abrasion with the same force, its hardness is said to he 4. If with more facility than 4, but less than 5, the hardness may be 4¿ or 4£, written in decimals... | |
 | William Elderhorst - 1873 - 314 lapas
...6. Orthoclase; white cleavable variety. 7. Quartz; transparent. 8. Topaz; transparent. 9. Corundum; cleavable varieties. 10. Diamond. To test the hardness...facility than 4, but less than 5, the hardness may be 4.2 or 4.5. Several successive trials should be made to obtain certain results; and, when practicable,... | |
 | William Elderhorst - 1874 - 340 lapas
...6. Orthoclase; white cleavable variety. 7. Quartz; transparent. 8. Topaz; transparent. 9. Corundum ; cleavable varieties. 10. Diamond. To test the hardness...facility than 4, but less than 5, the hardness may be 4.2 or 4.5. Several successive trials should be made to obtain certain results ; and, when practicable,... | |
 | Charles Gilbert Wheeler - 1881 - 92 lapas
...Orthoclase; white cleavable variety. 7. Quartz; transparent. 8. Topaz ; transparent. 9. Corundum ; cleavable varieties. 10. Diamond. To test the hardness...facility than 4, but less than 5, the hardness may be 4.2 or 4.5. Several successive trials should be made to obtain certain results ; and, when practicable,... | |
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Talc ; common laminated light-green variety. 2. Gypsum ; crystalline variety. 3. Calcite ; transparent variety. 4. Fluorite ; crystalline variety. 5. Apatite; transparent variety. 6. Orthoclase; white cleavable variety. 7. Quartz; transparent. 8. Topaz;... 