228 



TABLE 208.— RELATIVE HARDNESS 



Agate 7. 



Alabaster .... 1.7 



Alum 2-2.5 



Aluminum . . .2.9 



Amber 2-2.5 



Andalusite . . .7.5 

 Anthracite . . .2.2 

 Antimony .... 3.3 



Apatite 5. 



Aragonite .... 3.5 



Arsenic 3.5 



Asbestos 5. 



Asphalt 1-2. 



Augite 6. 



Barite 3.3 



Hell-metal ....4. 



Heryl 7.8 



Bismuth . . .". .2.5 

 Boric acid .... 3. 



Brass 3-4. 



Calamine 5. 



Calcite 3. 



Copper . . .2.5-3. 

 Corundum ... .9. 

 Diamond .... 10. 

 Dolomite . . 3.5-4. 



Feldspar 6. 



Flint 7. 



Fluorite 4. 



Galena 2.5 



Garnet 7. 



Glass 4.5-6.5 



Gold 2.5-3. 



Graphite . . ..5-1. 

 Gypsum . . 1.6-2. 



Hematite 6. 



Hornblende . . . 5.5 



Iridium 6.5 



Iridosmium ... 7. 



Iron 4-5. 



Kaolin 1. 



Loess (0°) 3 



Magnetite ... .6. 



Marble 3-4. 



Meerschaum 2-3. 



Mica 2.8 



Opal 4-6. 



Orthoclase .... 6. 



Palladium 4.8 



Phosphor- 

 bronze 4. 



Platin- 



iridium . . . .6.5 



Platinum 4.3 



Pyrite 6.3 



Quartz 7. 



Rock-salt 2. 



Ross' metal. 2. 5-3.0 

 Serpentine .3-4. 



Silver 2.5-3. 



Silver 



chloride .... 1.3 



Steel 5-8.5 



Stibnite 2. 



Sulfur ...1.5-2.5 



Talc 1. 



Tin 1.5 



Topaz 8. 



Tourmaline . . .7.3 



Wax (0°) 2 



Wood's metal . . 3. 



TABLE 209.— RELATIVE HARDNESS OF THE ELEMENTS (MEANS) 



1.2 

 1.2 



.6 

 .5 

 .4 

 .3 

 .2 



SMITHSONIAN PHYSICAL TABLES 



