Candoluminescence is the term used to describe the light

Light

Light or visible light is electromagnetic radiation that is visible to the human eye, and is responsible for the sense of sight. Visible light has wavelength in a range from about 380 nanometres to about 740 nm, with a frequency range of about 405 THz to 790 THz...

 given off by certain materials which have been heated to incandescence

Incandescence

Incandescence is the emission of light from a hot body as a result of its temperature. The term derives from the Latin verb incandescere, to glow white....

 and emit a larger proportion of short wavelength

Wavelength

In physics, the wavelength of a sinusoidal wave is the spatial period of the wave—the distance over which the wave's shape repeats.It is usually determined by considering the distance between consecutive corresponding points of the same phase, such as crests, troughs, or zero crossings, and is a...

 light than would be expected for a typical blackbody radiator. The phenomenon is noted in certain transition metal

Transition metal

The term transition metal has two possible meanings:*The IUPAC definition states that a transition metal is "an element whose atom has an incomplete d sub-shell, or which can give rise to cations with an incomplete d sub-shell." Group 12 elements are not transition metals in this definition.*Some...

 and rare earth

Rare earth element

As defined by IUPAC, rare earth elements or rare earth metals are a set of seventeen chemical elements in the periodic table, specifically the fifteen lanthanides plus scandium and yttrium...

 metal oxide materials (ceramic

Ceramic

A ceramic is an inorganic, nonmetallic solid prepared by the action of heat and subsequent cooling. Ceramic materials may have a crystalline or partly crystalline structure, or may be amorphous...

s) such as zinc oxide

Zinc oxide

Zinc oxide is an inorganic compound with the formula ZnO. It is a white powder that is insoluble in water. The powder is widely used as an additive into numerous materials and products including plastics, ceramics, glass, cement, rubber , lubricants, paints, ointments, adhesives, sealants,...

 and cerium oxide

Cerium(IV) oxide

Cerium oxide, also known as ceric oxide, ceria, cerium oxide or cerium dioxide, is an oxide of the rare earth metal cerium...

 or thorium dioxide

Thorium dioxide

Thorium dioxide , also called thorium oxide is a white, crystalline powder. It was formerly known as thoria or thorina. It is produced mainly as a by-product of lanthanide and uranium production.[1]...

, where some of the light from incandescence causes fluorescence

Fluorescence

Fluorescence is the emission of light by a substance that has absorbed light or other electromagnetic radiation of a different wavelength. It is a form of luminescence. In most cases, emitted light has a longer wavelength, and therefore lower energy, than the absorbed radiation...

 of the material. Calcium oxide

Calcium oxide

Calcium oxide , commonly known as quicklime or burnt lime, is a widely used chemical compound. It is a white, caustic, alkaline crystalline solid at room temperature....

 also has this effect which is called limelight

Limelight

Limelight is a type of stage lighting once used in theatres and music halls. An intense illumination is created when an oxyhydrogen flame is directed at a cylinder of quicklime , which can be heated to 2572 °C before melting. The light is produced by a combination of incandescence and...

. The cause may also be due to direct thermal excitation of metal ions in the material. Candoluminescence may also sometimes be used informally to describe any material heated to incandescence specifically by a flame

Flame

A flame is the visible , gaseous part of a fire. It is caused by a highly exothermic reaction taking place in a thin zone...

. The most common examples of candoluminescence can be found in the glowing cerium/thorium (ratio of ~1:99) oxide mesh of a kerosene lamp

Kerosene lamp

The kerosene lamp is a type of lighting device that uses kerosene as a fuel. This article refers to kerosene lamps that have a wick and a tall glass chimney. Kerosene lanterns that have a wick and a glass globe are related to kerosene lamps and are included here as well...

 mantle or gas mantle

Gas mantle

An incandescent gas mantle, gas mantle, or Welsbach mantle is a device for generating bright white light when heated by a flame. The name refers to its original heat source, existing gas lights, which filled the streets of Europe and North America in the late 19th century, mantle referring to the...

and in an old style Limelight.

It is not clear that a separate physical phenomenon called candoluminescence is required to explain the behavior of Welsbach mantles or limelight. Thorium oxide has very low emissivity in the near infrared and visible parts of the spectrum. Without cooling by infrared radiation, a mantle can get closer to the flame temperature than can a black body material. The higher temperature leads to higher emission levels in the visible portion of the spectrum. Cerium dioxide was made part of the mantle composition to enhance radiative cooling by the emission of visible light.