Fireclay tile has a turquoise ceramic tile. In a more budget tile, you might look at Daltile's Natural Hues line. They don't have what I consider to be a "true" turquoise, but they do have some blue-greens that might suit.

Here is a link that might be useful: Fireclay Tile Colors

See these, too.

Dunis Studios
Mercury Mosaics

Both websites have issues with phones and tablets, and are more useful if viewed via computer. I know some FL designers use Dunis, but I am not sure where they are.
Ed. to add a link.

Here is a link that might be useful: Okay, I found a showroom link

This post was edited by kitchendetective on Tue, Dec 30, 14 at 20:19

Dal-Tile's Festiva line has two colors that might be it, and a 3x6 subway - Sea Mist and Bermuda. One is clear, the other muted but they looked turquoise to me.

http://products.daltile.com/series.cfm?series=56&item=872&;

http://products.daltile.com/series.cfm?series=56&item=858&;