Rocks are rated on the on the Moh's Hardness Scale which rates the rocks on the scale from 1 to 10. Rocks with hardness 1-3 are soft rocks from 3-6 are medium hardness rocks and 6-10 are hard rocks. The hardness of Limestone is 3-4 whereas its compressive strength is 115.00 N/mm 2. Streak is the color of rock when it is crushed or powdered. The

The density of limestone ranges from 1.5 to 2.7 g/cm3. Limestones integrate a Mohs hardness of 2 to 4. Dense limestones have a crushing strength of up to 180 MPa. The limestones fizz when a drop of dilute hydrochloric acid is placed on them. Limestone exhibits fine, medium, and coarse textures depending on the environment of formation.

Limestone is a sedimentary rock composed primarily of calcite, a calcium carbonate mineral with a chemical composition of CaCO3. It usually forms in clear, 

The fluorite crystals, arguably, are the most desirable of all of the limestone occurrences in south-western Ontario. The best are ultra-gemmy, lustrous, deep blue or purple and up to 35mm or so in size, although most are less that 25mm on-edge. More commonly, they are light lavender to colourless.

The Hardness Of Rocks And Minerals. The hardness of fine-grained rocks tends to reflect the average hardness of the minerals in them. Shales are made mostly of clay and

Limestone hardness refers to the soft or hard and smooth mineral structure of limestone crystals. Agricultural and horticultural limestones are considered soft crystals, reacting quickly with acid, which are more desirable in adjusting the pH of substrates formulated with peat moss, pine bark or coconut coir.

The limestone rock is not siliceous and has no abrasive qualities to spoil the cutting edge of the bit, but if you should consider only the 

Limestone Rocks on the Beach; Limestone is a sedimentary rock such as greater than 50% calcium carbonate ( calcite – CaCO3). There are many exceptional kinds of limestone formed

There are various formations of rock with various PSI ratings. This chart provides the Approximate MOH Hardness for each formation.

limestone, sedimentary rock composed mainly of calcium carbonate (CaCO3), usually in the form of calcite or aragonite.

The limestone rock is not siliceous and has no abrasive qualities to spoil the cutting edge of the bit, but if you should consider only the first minute in the Barre granite you would find that the penetration rate per minute was higher than it was in limestone. Another substance which is hard to drill is hornblende-gneiss.