👉 Pentrite is a type of rock that contains three different types of minerals, each with its own unique properties. The name "pentrite" comes from its shape, which resembles a triangle or a pentagon. These minerals are primarily composed of quartz (also known as quartzite), feldspar (also known as calcite), and plagioclase (a type of amphibole). Pentrite is often used in geology for its unique properties and as an example of what can occur