This is the 12094th most frequent French word.
turquoise
A blue-green color or a precious gemstone of the same hue.
In this sentence, 'turquoise' is used as an adjective describing the specific shade of blue of the sea.
La mer était d'un bleu turquoise magnifique.
The sea was a beautiful turquoise blue.
Here, 'turquoise' is used as a noun describing the gemstone material of the necklace.
Elle portait un collier en turquoise qui scintillait au soleil.
She wore a turquoise necklace that sparkled in the sun.
In this usage, 'turquoise' refers to the specific color resulting from the combination of blue and green.