Definition

A type of rock that is mostly made up of a mineral called feldspar, often found in the Earth's crust.

Example

Anorthosite is commonly used in construction and as a decorative stone.

Conversation

Have you ever heard of anorthosite?

I don't think so, what is it?

It's a type of rock that's mostly made of feldspar.

Interesting! I didn't know there were so many types of rocks.

Synonyms & Antonyms

Root Explanation

Anorthosite is formed from "an-" (meaning not) and "orthos" (from Greek, meaning straight or correct) and "-ite" (a suffix used in mineralogy to denote a type of rock or mineral). The word describes a type of rock that is not composed of the usual plagioclase feldspar but rather consists predominantly of anorthite, which is a type of feldspar that is considered 'not straight' in its composition compared to other feldspars.

Memory Tip

Think of 'not' ('an-') and 'straight' ('orthos') to remember that anorthosite is a rock that is not composed of the usual straight or typical minerals.

Visually Confused Words