timanttiveitsi

Timanttiveitsi, or diamond knife, is a cutting tool whose edge is made from diamond. It is used to produce extremely smooth, ultra-thin sections of hard or delicate materials, enabling precise analysis in microscopy and high-precision cutting in materials science. The knife’s exceptional hardness and edge stability allow for consistent section quality and longer tool life compared with other blade materials.

In histology and electron microscopy, diamond knives are employed for ultramicrotomy of resin-embedded samples to generate ultra-thin sections for transmission electron microscopy (TEM) and, to a lesser extent, for light microscopy. These sections typically range from tens to a few hundred nanometers in thickness. Diamond knives are mounted on ultramicrotomes and used with carefully prepared cut sections to minimize compression and artifacts.

Types and construction vary. Diamond knives can use monocrystalline or polycrystalline diamond and are typically mounted on steel or glass carriers. The knife edge is ground to precise bevels, with bevel angles and blade geometry chosen to suit the material and desired section thickness. Because diamond knives are brittle and expensive, they require careful handling, storage, and periodic re-sharpening or re-edging by specialized services.

Advantages include extreme hardness, wear resistance, and the ability to produce very smooth, undistorted sections, contributing to high reproducibility in sample preparation. Limitations are the high cost, fragility, and the need for skilled operation and compatible equipment.

History notes that diamond knives became widespread in microtomy after advances in synthetic diamond production in the mid-20th century, offering more consistent performance than natural diamonds.