Sandpaper, also known as glasspaper, is a heavy paper
Paper is a thin material mainly used for writing upon, printing upon, drawing or for packaging. It is produced by pressing together moist fibers, typically cellulose pulp derived from wood, rags or grasses, and drying them into flexible sheets....

 with abrasive
An abrasive is a material, often a mineral, that is used to shape or finish a workpiece through rubbing which leads to part of the workpiece being worn away...

 material attached to its surface.

Sandpaper is part of the "coated abrasive
Coated abrasive
A coated abrasive is an abrasive grain bonded to a flexible substrate using adhesives. Common substrates are paper, cloth, vulcanized fiber, and plastic films and come in grit sizes range from very coarse to ultrafine...

s" family of abrasive products. It is used to remove small amounts of material from surface
In mathematics, specifically in topology, a surface is a two-dimensional topological manifold. The most familiar examples are those that arise as the boundaries of solid objects in ordinary three-dimensional Euclidean space R3 — for example, the surface of a ball...

s, either to make them smoother (paint
Paint is any liquid, liquefiable, or mastic composition which after application to a substrate in a thin layer is converted to an opaque solid film. One may also consider the digital mimicry thereof...

ing and wood finishing
Wood finishing
Wood finishing refers to the process of embellishing and/or protecting the surface of a wooden material. The process starts with surface preparation, either by sanding by hand , scraping, or planing. Imperfections or nail holes on the surface may be filled using wood putty or pores may be filled...

), to remove a layer of material (e.g. old paint), or sometimes to make the surface rougher (e.g. as a preparation to gluing
An adhesive, or glue, is a mixture in a liquid or semi-liquid state that adheres or bonds items together. Adhesives may come from either natural or synthetic sources. The types of materials that can be bonded are vast but they are especially useful for bonding thin materials...

The first recorded instance of sandpaper was in 13th century China
Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...

 when crushed shells, seeds, and sand were bonded to parchment using natural gum.

Sharks are a type of fish with a full cartilaginous skeleton and a highly streamlined body. The earliest known sharks date from more than 420 million years ago....

 skin was also used as a sandpaper.