Materials (Hierarchy Name)

The Materials hierarchy contains descriptors for a broad range of substances, from natural and synthetic raw materials to material products. Material products are included here rather than in the Objects facet because they can be used in the construction of various objects (e.g., "plank" for floors or walls), and because they are not necessary constituent parts of objects (e.g., "shingle" is not essential to roofs in the same way as roof ridges or eaves).Relation to Other Hierarchies: Descriptors denoting activities performed on or with materials are found in the Processes and Techniques hierarchy (e.g., "glassworking"). descriptors for object types defined by the material from which they are made are found in the Object Genres hierarchy (e.g., "metalwork", "textiles") while descriptors for the materials themselves are found here ("metal", "textile"). Descriptors for tools used in the creation of images (e.g., "charcoal sticks", "pens") appear in the Tools and Equipment hierarchy, while descriptors for the materials of which they are made or which they use are found here ("charcoal", "ink").