Texture is a surface and visual tactile attribute of a form or composition. This is a very easy way of "telling" your audience's eyes what their hands may feel.
Texture and Volume
Texture can be greatly enhanced by form and volume, take an orb of a grainy earth texture and lay it on a glossy floor to see the effect of value and volume on texture.
Implicated TexturesUsing multiple styles of textures can add levels of contrast and dimensionality to your compositions.