Diamond knife

In 1950, Latta and Hartmann discovered that the edge of broken glass could be used to cut thin sections of specimens for transmission electron microscopy.

[3] Some hard specimens, such as bone, plants, thick-walled spores, metals and ceramics are difficult to cut, even with a good glass knife, because the edge dulls too quickly.

[10][11][12] Humberto Fernández-Morán discovered that a gem-quality diamond, the hardest known material, could be used to fabricate a more durable knife for use in the ultramicrotomy.

Natural gemstones used to produce diamond knives are usually pale yellow, of regular crystal structure and of the greatest possible purity.

The knife's edge is extremely sharp and free of imperfections, which helps produce ultrathin sections of very regular thickness to get views of specimens at high magnifications with the transmission electron microscope (TEM).