diamond point engraving

…suitable for engraving with a diamond point, a technique which produced spidery opaque lines that were especially suitable for delicate designs. The technique seems to have come into use about 1530.

…particularly favoured by the Dutch diamond-point engravers, whose work in this period was executed almost exclusively in stipple (i.e., dotted engraving). The chief masters of this delicate art, in which the design seems no more than a bloom on the surface of the glass, were Frans Greenwood of Dordrecht, the…