Geology

Basic geology helps identify stone and its properties

Four types of rock:

• SEDMINTARY: sand, gravel and organic material compacted and cimented
  • observable layers
  • hardness: soft
  • does not retain polish
  • sandstone: silica (sand, quartz)
  • limestone: fossils of algae, shells, bones (no silica)
  • conglomerate: mud and gravel
• VOLCANIC: extrusive magma
  • lava cooled quickly when exposed to air or water
  • small crystals
  • can be polished
• PLUTONIC: intrusive magma:
  • magma that cooled slowly in the Earth’s interior
  • large crystals, or complete crystalization
  • uniform granular texture
  • can be polished
  • contains silica (quartz), mica and feldspar
• METAMORPHIC:
  • existing rock transformed by heat and pressure
  • observable folding or distorted strata
  • ex. marble (transformed sedimentary)
  • ex. gneiss (transformed granite)

Québec geoscientific database

• SIGÉOM 150 years of data from mining and mapping surveys

A basic knowledge of geology means you don't use limestone for foot traffic areas or wet areas such as countertops, and you don’t use iron tools on granite (use carbide-tipped chisels or tempered steel).