Which of these are essential non-metallic minerals?

Coal, silica, clay, and cement are considered essential non-metallic minerals.

Key PointsCoal: While coal is primarily composed of carbon and some other elements, it is classified as a non-metallic mineral. It is a crucial source of energy and is used extensively for electricity generation, as well as in industrial processes.

1. Silica (Quartz): Silica is indeed a non-metallic mineral and is essential in various industries. It is a key component in the production of glass, ceramics, and electronics. Additionally, silica is used in the manufacturing of silicon for semiconductors.

2. Clay: Clay is a non-metallic mineral and is widely used in the production of bricks, ceramics, and pottery. Different types of clay find applications in industries like construction, pharmaceuticals, and cosmetics.

3. Cement: Cement is not a mineral itself, but it is made from minerals. The primary component of cement is limestone (a non-metallic mineral), which is ground and heated to produce the powder used in construction for making concrete. Cement plays a vital role in the building and infrastructure industries.

Additional InformationNon-metallic minerals are minerals that do not contain metal elements. They are essential for various industrial processes, construction, and manufacturing.

The other options aren't correct as they are metallic in nature.