Basically, turquoise is a mixture of blue and green. Knowing the right ratios and color bias to get your desired shade of turquoise is more complicated.
Turquoise as a versatile, vibrant color that can enhance any artwork.
Turquoise falls between blue and green on the color wheel. It is typically placed closer to the blue side, as it is often considered a variant of blue with green added.
Phthalo blue, cerulean blue, or cobalt blue would be good choices. Turquoise blue can also be mixed using ultramarine blue, even though it leans more toward purple.
Add a tiny amount of yellow or burnt umber for an earthier, muted turquoise
Add a tiny touch of orange or alizarin crimson to get a muted or toned-down turquoise.
Experiment with your own colors, mixing your greens and blues and swatching them on a sheet of card stock or watercolor paper so that you can see what color mixes you like best.