Which of the following is NOT a type of alloy?

Granite is the correct choice as it is not an alloy. An alloy is a mixture of two or more elements, typically including at least one metal, that are combined to enhance properties such as strength, durability, and resistance to corrosion.

Brass, which is an alloy of copper and zinc, is known for its malleability and acoustic properties, making it suitable for musical instruments and decorative items. Bronze, another alloy, primarily consists of copper and tin, and is valued for its hardness and resistance to corrosion, widely used in sculptures and industrial applications. Pewter is an alloy that usually consists of tin and small amounts of other metals, commonly used in household items and decorative objects.

Granite, on the other hand, is a natural stone composed primarily of quartz, feldspar, and mica, and does not fit the definition of an alloy. Its properties come from the minerals it is composed of, rather than a combination of metals to create enhanced characteristics.