Polishing is the process of creating a smooth and shiny surface by rubbing it or using a chemical action, leaving a surface with a significant specular reflection

Specular reflection

Specular reflection is the mirror-like reflection of light from a surface, in which light from a single incoming direction is reflected into a single outgoing direction...

 (still limited by the index of refraction of the material according to the Fresnel equations

Fresnel equations

The Fresnel equations , deduced by Augustin-Jean Fresnel , describe the behaviour of light when moving between media of differing refractive indices...

.) In some materials (such as metals, glasses, black or trasparent stones) polishing is also able to reduce diffuse reflection

Diffuse reflection

Diffuse reflection is the reflection of light from a surface such that an incident ray is reflected at many angles rather than at just one angle as in the case of specular reflection...

 to minimal values. When an unpolished surface is magnified thousands of times, it usually looks like mountains and valleys. By repeated abrasion, those "mountains" are worn down until they are flat or just small "hills." The process of polishing with abrasive

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...

s starts with coarse ones and graduates to fine ones.

Polishing with very fine abrasive differs physically from coarser abrasion, in that material is removed on a molecular level, so that the rate is correlated to the boiling point rather than to the melting point of the material being polished.

Metalworking

Other polishing processes include:

• Burnishing
  Burnishing (metalworking)
  Burnishing is the plastic deformation of a surface due to sliding contact with another object. Visually, burnishing smears the texture of a rough surface and makes it shinier...
  
  
• Mass finishing
  Mass finishing
  Mass finishing is a group of manufacturing processes that allow large quantities of parts to be simultaneously finished. The goal of this type of finishing is to burnish, deburr, clean, radius, de-flash, descale, remove rust, polish, brighten, surface harden, prepare parts for further finishing, or...
  
  
  • Tumble finishing
  • Vibratory finishing
    Vibratory finishing
    Vibratory finishing is a type of mass finishing manufacturing process used to deburr, radius, descale, burnish, clean, and brighten a large number of relatively small workpieces....
    
    
• Sodablasting
  Sodablasting
  Sodablasting is a process in which sodium bicarbonate is applied against a surface using compressed air. An early use was to restore the Statue of Liberty in the late 1980s....
  
  

Other

• Chemical-mechanical polishing, which is used in semiconductor fabrication
• Fabrication and testing of optical components
• Flame polishing
  Flame polishing
  Flame polishing is a method of polishing a material, usually thermoplastics or glass, by exposing it to a flame or heat. By melting the surface of the material, surface tension smooths the surface out. Operator skill is critical with this method. When done properly, flame plastic polishing produces...
  
  , a type of polishing used on glass and thermoplastics
• Ultra-fine, abrasive paste polishing, polishing for soft or fragile work surfaces
• Vapor polishing
  Vapor Polishing
  Vapor polishing is a method of polishing plastics to reduce the surface roughness or improve clarity. Typically, a component is exposed to a chemical vapor causing the surface to flow thereby improving the surface finish. This method of polishing is frequently used to return clear materials to an...
  
  , a method of polishing plastics to optical clarity