Sedimentary stone is generated by the hardening of layers by pressure and heat, usually under water. It consists of strata or layers of sand, clay or natural sediments. The hardness and strength of stone varies.
Examples: Flagstone, sandstone, shale and limestone Igneous rock is made of molten material which cools and becomes strong. It may have been molten lava at shallow depths or magma.
Examples: Granite, basalt Metamorphic rocks are formed when heat, pressure, fluids and strain act to transform sedimentary or igneous rocks into materials. This is what transforms sandstone into quartzite and limestone into marble under heat and pressure.
Examples: Quartzite, marble What this means for you… Sedimentary sandstone from Arizona has been used in flagstone patios in the early 1900s, so there’s been a long time to test its suitability. Pale color and resistance to heat absorption has made it a prevalent selection in the Southwest where swimming pool decking may become hot in the summer. Still, the porosity of this material makes it problematic too, and in many conditions home owners are redoing their patios with harder flagstone alternatives like quartzite for these reasons:
Compounds absorbed into sandstone can expand to induce flaking. Issues occur next to irrigated areas due to overspray. Hard freezing may lead to displacement of episodes. Swimming pool that is chlorinated may create large harm. Wear and tear causes gradual erosion of the surface which leads to low spots. Areas where water slides can render large stains on the stone itself. Years of grilling and clogs spatter can discolor sandstone. Igneous rock is made of molten material which cools and becomes strong. It may have been molten lava at shallow depths or magma.
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