The hundreds of materials for use by engineers are classified in various ways and no classification system encompasses every material or application. Some common approaches for organizing materials are by:

• Fundamental properties.  These typically divide materials into common atomic properties; the most basic and well-known system is the periodic table of elements, which works well for elements but less so for composites or particular applications.
• Physical properties, such as density, gravity, thermal conductivity, or magnetism.
• Mechanical or performance properties, such as tensile strength, creep, toughness, or fatigue.
• Suitability for specific circumstances, such as resistance to damage from fires, water, or vibrations; or biocompatibility with humans or animals.
• Industrial applications, such as pharmaceuticals, building construction, electronics, or packaging.
• Appearance, such as color, texture, or reflectivity.

This section presents mini-guides for major groups of materials.  Some are based on materials which share atomic bonding characteristics.  Others focus on materials for two important applications – biomedical/biotechnology engineering and semiconductors, which are of particular interest in electrical and computer engineering, nanotechnology, and renewable energy.