An extract from the "Dictionary of Arts and Sciences" dated 1754

LAPIDARY, an artificer, who cuts precious stones. See the article GEM.
The art of cutting precious stones is of great antiquity. The French, tho' they fell into it but lately, have notwithstanding carried this art to a very great perfection, but not in any degree superior to the English.
There are various machines employed in the cutting of precious stones, according to their quality: the diamond, which is extremely hard, is cut on a wheel of soft steel turned by a mill, with diamond dust tempered with olive oil, which also serves to polish it.

The description of the diamond-cutters wheel or mill, as represented in Plate CLII.fig.5 is as follows.
a is the pincers ; b, the screw of the pincers ; c, the shell that carries the mastic and the diamond ;d, the mastic that softens the diamond at the end of the shell ; e, the diamond presented to the wheel, to be cut facetwise ; f, the iron wheel turning on its pivot ; g, iron pegs, to fix and keep the pincers steady ; h, small pigs of lead of different weights, wherewith the pincers are loaded at pleasure to keep them steady ; i, a wooden wheel ; k, the axe of the wheel . It is bended and makes an elbow under the wheel, to receive the impulsion of a bar that does the office of a turning handle ; l, the sole or square piece of steel wherin the pivot of the tree or axis moves ; m, the turning handle that sets the wheel a-going by means of the elbow of its axis. The elbow of the piercer wherewith a hogshead is broached, will give an idea of this kind of motion ; n, the catgut string that goes around both the iron and the wooden wheels. If the wooden wheel is twenty times larger than the iron-one, the latter shall make twenty turns upon the diamond, whilst the large makes but one around its axis ; and whilst the boy gives, without any resistance a hundred impulsions of the turning handle, the diamond experiences a thousand times the friction of the whole grinding wheel.
The diamond cutter follows the work with his eyes, without taking any other share in it than of changing the place of the diamond to bite on a new surface ; and of timely throwing upon it, with a few drops of oil, the minute particles of the diamond's first ground one against the other, to begin the cutting of them.
The oriental ruby, sapphire, and topaz are cut on a copper wheel with diamond-dust, tempered with olive oil, and are polished on another copper wheel with tripoli and water. The hyacinth, emerald, amethyst, garnets, agates, and other stones, not of an equal degree of hardness with the other, are cut on a leaden wheel with smalt and water, and polished on a tin-wheel with tripoli. The turquois of the old and new rock, girasol and opal, are cut and polished on a wooden wheel with tripoli also.
The lapidaries of Paris have been a corporation since the year 1290. It is governed by four jurats, who superintend their rights and privileges, visit the master workmen, take care of the master-piece of workmanship, bind apprentices, and administer the freedom.