Bleu celeste is a rarely occurring tincture

Tincture (heraldry)

In heraldry, tinctures are the colours used to emblazon a coat of arms. These can be divided into several categories including light tinctures called metals, dark tinctures called colours, nonstandard colours called stains, furs, and "proper". A charge tinctured proper is coloured as it would be...

 in heraldry

Heraldry

Heraldry is the profession, study, or art of creating, granting, and blazoning arms and ruling on questions of rank or protocol, as exercised by an officer of arms. Heraldry comes from Anglo-Norman herald, from the Germanic compound harja-waldaz, "army commander"...

 (not being one of the seven main colours or metals or the three "staynard colours"). This tincture is sometimes also called ciel or simply celeste. It is depicted in a lighter shade than the range of shades of the more traditional tincture azure

Azure

In heraldry, azure is the tincture with the colour blue, and belongs to the class of tinctures called "colours". In engraving, it is sometimes depicted as a region of horizontal lines or else marked with either az. or b. as an abbreviation....

, which is the standard blue used in heraldry.

Initially considered to be European rather than English

England

England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...

 or Scottish

Scotland

Scotland is a country that is part of the United Kingdom. Occupying the northern third of the island of Great Britain, it shares a border with England to the south and is bounded by the North Sea to the east, the Atlantic Ocean to the north and west, and the North Channel and Irish Sea to the...

, after the First World War it became more prevalent in England

England

England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...

 in badges of coats relating to the Royal Air Force

Royal Air Force

The Royal Air Force is the aerial warfare service branch of the British Armed Forces. Formed on 1 April 1918, it is the oldest independent air force in the world...

, or the arms of those with some RAF connection. While in the post-WWI period bleu-celeste is depicted as a darker shade, in prior times it was depicted as very light, and has even been treated as a metal, as azure

Azure

In heraldry, azure is the tincture with the colour blue, and belongs to the class of tinctures called "colours". In engraving, it is sometimes depicted as a region of horizontal lines or else marked with either az. or b. as an abbreviation....

 charges have been placed on a bleu celeste field, and vice versa.

Bleu celeste can be seen in the coat of arms of Argentina

Coat of arms of Argentina

The coat of arms of Argentina was established in its current form in 1944, but has its origins in the seal of the General Constituent Assembly of 1813. It is supposed that it was chosen quickly because of the existence of a decree signed on February 22 sealed with the symbol...

, Peru

Coat of arms of Peru

The coat of arms of Peru is the national symbolic emblem of Peru. Four variants are used: the coat of arms per se ; the national coat of arms, or national shield ; the great seal of the state ; and the naval coat of arms .-Description:All four share the same escutcheon or shield,...

 and also in the arms of the Canadian

Canada

Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...

 Governor General Ray Hnatyshyn

Ray Hnatyshyn

Ramon John Hnatyshyn , commonly known as Ray Hnatyshyn, was a Canadian politician and statesman who served as Governor General of Canada, the 24th since Canadian Confederation....

. In the arms of the University of Natal

University of Natal

The University of Natal was a university in Natal, and later KwaZulu-Natal in South Africa, that is now part of the University of KwaZulu-Natal. It was founded in 1910 as the Natal University College in Pietermaritzburg, and expanded to include a campus in Durban in 1931. In 1947, the university...

 Athletic Union the azure is defined as "sky blue".

In addition to bleu celeste, there is also an apparently unique example in British heraldry of the use of "light blue" in the Municipal Borough of Barnes

Municipal Borough of Barnes

Barnes was a local government district in north west Surrey from 1894 to 1965.It was formed as an urban district in 1894 and became a municipal borough in 1932....

, through which the Oxford versus Cambridge boat race passes on the Thames. The arms show the respective blades of the teams' oars, and may be blazoned thus:

Azure, on a saltire or between four ostrich feathers argent, two oars in saltire proper, the blade of that to the dexter dark blue and that to the sinister light blue. (Blue with a yellow saltire "x" between four white feathers, the two paddles crossed and lying along and atop the saltire)

When in 1965 that borough merged with its neighbours to form the Borough of Richmond upon Thames

London Borough of Richmond upon Thames

The London Borough of Richmond upon Thames is a London borough in South West London, UK, which forms part of Outer London. It is unique because it is the only London borough situated both north and south of the River Thames.-Settlement:...

, the coloured oars were transferred to the supporters in the arms of the new borough.