Colcothar is a mineral also known as red iron oxide, that has been used as a pigment since ancient times. Its spelling, /kɒlkəθər/, reflects the pronunciation of its Greek origin. The first syllable "col" is pronounced like "coal" and the second syllable "coth" sounds like "coth" in "scuba cloth". The final syllable "-ar" is pronounced like "are" in "stare". The word may be challenging to spell as it is uncommon and includes unusual letter combinations.
Colcothar, also known as red iron oxide or rouge, is a mineral pigment that is commonly used for its deep red color. It is a natural iron oxide compound that contains varying amounts of iron and oxygen. The name "colcothar" is derived from the Ancient Greek word "kolcothar," which means "colored earth," reflecting its earthy red hue.
Colcothar is typically obtained as a byproduct of steel production or as a result of the weathering of iron-rich minerals. It is usually found in the form of a powder or a solid, and its color can range from a deep red to a reddish-brown shade, depending on its purity and composition.
Due to its intense red color, colcothar has been widely used as a pigment in paints, dyes, and ceramics. It is particularly valued for its opacity and lightfastness, meaning it retains its color when exposed to sunlight or other sources of light for extended periods. Colcothar is also utilized in the production of polishing compounds, as it has abrasive properties that allow for the smoothing and buffing of surfaces.
In addition to its pigment and polishing applications, colcothar has played a role in traditional medicine and cosmetics. It is believed to have astringent properties, making it suitable for treating skin conditions and wounds. Historically, it has been used as a facial cosmetic, applied to the cheeks and lips to impart a rosy glow.
Overall, colcothar is a versatile mineral pigment prized for its vibrant red color, durability, and diverse range of applications in various industries.
Red oxide of iron, ferri oxidum rubrum.
A practical medical dictionary. By Stedman, Thomas Lathrop. Published 1920.
The brown-red peroxide of iron, produced by calcining sulphate of iron, used for polishing glass, &c.
Etymological and pronouncing dictionary of the English language. By Stormonth, James, Phelp, P. H. Published 1874.
The word "Colcothar" has an interesting etymology. It originates from the Arabic term "qalqadar", which means "light-colored iron oxide". This Arabic term was then borrowed into Medieval Latin as "colcotharum". The word further evolved and was later adapted into English as "Colcothar", while retaining its original meaning of a red-brown ferric oxide obtained by roasting iron sulfate.