shale

Everyday

1. Shale is a soft grey or dark rock made of hardened mud or clay that splits easily into thin flat layers. tree →
2. Shale is also a source of oil and gas that companies drill for. tree →

In the lessons

In geography and science it is a sedimentary rock, made when mud settles and is pressed over millions of years; fossils are often found in it; in news it comes with «shale gas» and «fracking»; phrases: shale gas, shale oil, oil shale.

Examples

• The cliff was made of crumbly grey shale. tree →
• Shale splits into thin flakes when you tap it. tree →
• We found a fossil fern in a piece of shale. tree →
• Shale is a sedimentary rock made from mud. tree →
• Some companies drill deep into shale to get gas. tree →
• The path was slippery with loose shale. tree →

Note

Usually uncountable: «some shale», «a piece of shale». Do not confuse with «slate», which is shale changed by heat and pressure into a harder rock; and with «shell».