Dorado vs. áureo
In Spanish, both dorado and áureo can be translated as "golden". However, they are not always interchangeable. The main difference lies in their frequency of use and connotation, with dorado being the common, everyday term and áureo being a more literary, formal, and elevated word.
Dorado
A2This is the most common and versatile word for "golden". It primarily refers to the color gold or something that is gold-plated or gilded (covered in a thin layer of gold). It is also used in cooking to describe food fried to a golden-brown color. Figuratively, it can refer to a prosperous period. It is also the name of a type of fish (mahi-mahi or dolphinfish).
El atardecer pintó las nubes de un hermoso color dorado.
(The sunset painted the clouds a beautiful golden color.)
Compró un espejo con un marco dorado muy elegante.
(She bought a mirror with a very elegant golden frame.)
Fríe las cebollas hasta que estén doradas.
(Fry the onions until they are golden brown.)
Fue la época dorada de su carrera como músico.
(It was the golden age of his career as a musician.)
Para la cena, prepararon un filete de dorado a la parrilla.
(For dinner, they prepared a grilled mahi-mahi fillet.)
Áureo
C1This is a more cultured, poetic, and formal word. It often implies that something is literally made of gold, not just gold-colored. It is frequently used in literary, historical, or mythological contexts to convey splendor, value, and nobility. It's also used in specific technical terms.
El tesoro incluía una máscara áurea de incalculable valor.
(The treasure included a golden mask of incalculable value.)
El poeta describió sus cabellos como hilos áureos.
(The poet described her hair as golden threads.)
El Siglo de Oro es también conocido como la Edad Áurea de España.
(The Golden Century is also known as the Golden Age of Spain.)
El Partenón fue diseñado siguiendo la proporción áurea.
(The Parthenon was designed following the golden ratio.)
La leyenda habla de un vellocino áureo custodiado por un dragón.
(The legend tells of a golden fleece guarded by a dragon.)
Summary
In essence, use dorado for everyday descriptions of color, gilded objects, and cooking. It is the default, common word. Use áureo for a more formal, literary, or poetic effect, especially when referring to things made of solid gold, historical eras like the Edad Áurea (Golden Age), or technical concepts like the proporción áurea (golden ratio). While época dorada and Edad Áurea can both mean Golden Age, áureo carries a more classic and magnificent connotation.