👉 The term "trimstone" refers to a type of rock that is formed from the metamorphism of igneous rocks. It is composed primarily of quartz, feldspar, and mica, which are combined in a chemical reaction known as the quartz-feldspar-mica reaction. This process occurs at the surface of magma or lava that has cooled sufficiently to form the rock, resulting in a dense, hard, and semi-precious material. Trimstone is often used for construction, landscaping