There are three sorts, one perfect Blue, and very hard, which if cut of a Diamond-Cut, and without Calcedone, is of very good Esteem, and worth a good Price, if it be in perfection.
The second is perfect White, and very hard, which if without blemish, Diamond-Cut, is likewise in Esteem.
The third, called Water-Saphires, are of small Esteem, being not so hard as the other, and commonly of a dead Waterish Colour; they are of a slender Value.