Mohs Hardness of Common Minerals ; Serpentine, 3 to 5 ; Siderite, 3.5 to 4.5 ; Sillimanite, 6.5 to 7.5 ; Silver, 2.5 to 3 ; Sodalite, 5.5 to 6.

7/1 · The counter material (wear ball) used in this study was a silicon nitride spherical indenter of 6.35 mm in diameter. It was gathered in literature that one of the common mined rocks, granite, has

9/29 · Rock Hardness & Drilling. A survey of the technical literature concerned with oil well drilling methods and particularly with rate of penetration by various cutting media on different types of rock provides a mass of conflicting data. This is especially true with respect to, (1) the relative efficiency of diamond, rotary and percussion drilling

The Mohs Hardness Scale is used as a convenient way to help identify minerals. A mineral's hardness is a measure of its relative resistance 

Hardness is how hard the rock is and on being scratched how much of a mark it will leave. There is a scale to messure the hardness of any rock or mineral of 10 being the hardest and 1 being the softest like in the picture to the left. The hardest on this scale is

Talc – Gypsum – Calcite – Fluorite – Apatite – Feldspar – Quartz – Topaz – Corundum – Diamond - “Mohs Scale of Mineral Hardness ” should be 

Mineral. Hardness. Talc. 1. Gypsum (Selenite). 2. Calcite. 3. Fluorite been the traditional sentence used with this list since its inception by Moh in 

Due to different indenters, loads, and load durations, there are a variety of indentation hardness, mainly Brinell hardness, Rockwell hardness, Vickers hardness, and micro-hardness. ③ Rebound hardness Mainly used for metal materials.

Mineral Hardness Diamond 10 Zaire 1 cm. 14 carats Corundum 9 variety ruby, India 6 cm. Topaz 8 Mursinsk, Russia, 5cm across Seaman Museum specimen Quartz 7 variety amethyst, Guerro, Mexico 16 cm.

Definition ; 7. Quartz ; 7.5. Garnet ; 8. Topaz ; 8.5. Chrysoberyl.

Soapstone 1 · Slate 2.5-4 · Marble 3-4 · Limestone 3-4 · Travertine 4-5 · Sandstone 6-7 · Granite 6-7 · Natural Quartz 7.