Sand is an example of a mixture with different solid particles. Concrete is another example of solid mixture. A mixture is a combination of two different substances that do not chemically combine. Also, mixtures are substances with components that can be separated from the mixture. Solid mixtures are mixtures of two substances that result in a solid form.
Concrete is a mixture of lime, water, cement, sand and rocks. When these components are mixed together, the cement solidifies, forming a solid mixture. Although the hardening of the cement can be considered a chemical reaction, the actual mixture is held together by a physical force, and these components are still not chemically bonded.
Alloys are also considered as mixtures. Alloys are homogeneous mixtures of two or more kinds of metal. Brass is a mixture of 70 percent copper and 30 percent zinc. Bronze is 90 percent copper and 10 percent tin. Alloying metals is like dissolving one metal into another in order to improve its properties. It is just like dissolving salt in water, which is why alloys are considered to be a mixture rather than a compound. Another example of solid mixtures are precious stones like amethyst, topaz, opal and garnet. These stones are a combination of silicon dioxide and different kinds of metals.