What part of speech is turquoise?

"Turquoise" can be two parts of speech, depending on how it is used:

* Adjective: When describing something as having the color turquoise.

* Example: "She wore a turquoise dress."

* Noun: When referring to the color itself or the gemstone.

* Example: "Turquoise is my favorite color."

* Example: "The ring was set with a beautiful turquoise stone."