Non-metallic minerals are minerals that do not contain any metal elements and are therefore not malleable, ductile, or good conductors of heat and electricity. They have various industrial applications and are used for their physical properties such as hardness, lightness, and heat resistance. Out of the given options, the non-metallic mineral is coal.

Explanation:
Coal is a non-metallic mineral that is primarily composed of carbon along with small amounts of other elements such as hydrogen, sulfur, oxygen, and nitrogen. It is formed from the remains of plants that lived and died millions of years ago, and through geological processes, these plant materials were transformed into coal.

Coal is classified as a sedimentary rock and is mainly used as a fossil fuel for generating electricity and heat. It is also used in the production of steel, cement, and various industrial processes. Some of the key properties of coal include:

1. Combustibility: Coal is highly combustible and is used as a fuel source in power plants and industries.

2. Calorific value: It has a high calorific value, meaning it releases a large amount of heat energy when burned.

3. Carbon content: Coal contains a high percentage of carbon, which is responsible for its energy content.

4. Ash content: Coal also contains varying amounts of ash, which is the residual material left after the combustion process.

5. Moisture content: Coal can have varying moisture content, which affects its energy content and combustion efficiency.

6. Types of coal: There are different types of coal based on their carbon content and properties, such as anthracite, bituminous coal, sub-bituminous coal, and lignite.

In contrast, silver, copper, and zinc are metallic minerals. Silver is a precious metal used in jewelry, electrical components, and photography. Copper is a versatile metal used in electrical wiring, plumbing, and industrial applications. Zinc is also a metal used in galvanizing steel, producing alloys, and as a dietary supplement.

Therefore, the correct answer is option D, coal, as it is a non-metallic mineral.