Krüss microscope refers to gemmological microscopes manufactured by A. Krüss Optronic GmbH of Hamburg, Germany. The Krüss firm was founded in 1796 and has produced precision optical instruments continuously for more than two centuries. Its modern catalogue includes a range of stereomicroscopes specifically configured for gemmological work, sold under model designations such as KSW8000 and KSW7000.

The standard Krüss gemmological microscope is a stereoscopic binocular instrument with a zoom magnification range typically from approximately 6.4× to 40× or 6.4× to 64×, depending on configuration. Standard accessories include darkfield and brightfield illumination, an iris diaphragm under the well, polarising filters, an immersion cell, and a stone-holding articulating arm. Optional fluorescence sources, fibre-optic illuminators, and digital camera attachments are available.

In gemmological practice, Krüss instruments compete with Eickhorst, Gemoro, GIA-branded scopes, and the higher tier of Leica and Nikon microscopes. The Krüss instruments are well-regarded in European laboratories and educational institutions, and are durable enough for everyday trade use. They are not specific to any single technique; the same body serves for inclusion identification, treatment detection, and routine quality grading.