The Olympus SZX is a premium series of stereo zoom microscopes manufactured originally by the Olympus Corporation and now by Evident Corporation (Olympus's life-science and industrial business, spun off as a separate company in 2022). The series is the standard equipment for inclusion observation, treatment determination, and photomicrography in gemmological research laboratories worldwide, with examples in active use at GIA, Gübelin, SSEF, AGL, and other major laboratories, as well as in academic gemmology programmes and high-end commercial gem houses. The SZX combines high optical quality with the modular illumination and accessory ecosystem that gem inclusion work requires.

Specifications and capabilities

The SZX series spans several models — including the SZX10, SZX12, and SZX16 — that share a common stereo design with separate left- and right-eye optical paths producing true three-dimensional viewing. Magnification ranges from approximately 0.5× to 11.5× on the zoom body alone, expanding to as much as 115× with high-magnification eyepieces and auxiliary lenses. The optical system uses Olympus's apochromatic correction (in the higher-end models) for chromatic-aberration-free imaging, and high numerical aperture for resolution sufficient to image subwavelength inclusion details.

The illumination system is modular. Standard configurations include dark-field substage illumination — where the light enters from below at an oblique angle, producing a black background against which inclusions appear bright — and bright-field illumination for more conventional viewing. Fibre-optic illuminators provide oblique, top-down, and ring-light sources, with the ability to combine multiple lighting modes for specific imaging tasks. The dark-field configuration is particularly important for gem inclusion work, where the contrast between included material and the host gem is most useful for identification.

Use in gem laboratory work

The SZX is the workhorse instrument for the visual identification stages of gemmological analysis. Inclusion observation under dark-field magnification — the basis of much of the standard gemmological identification protocol — is performed on instruments of this class, with the gemmologist examining the stone at varying magnifications to identify diagnostic inclusion features, treatment indicators, and other visual cues to species, variety, origin, and treatment history. Photomicrography for laboratory reports and publications is increasingly performed using digital cameras attached to the trinocular tube of the SZX, capturing high-resolution images that document the gemmologist's observations.

Specific gemmological tasks performed routinely on SZX-class instruments include: identification of growth structures characteristic of natural versus synthetic gem species; observation of treatment indicators such as discoidal heat-treatment fractures in corundum or oil residue in emerald; observation of mineral inclusions diagnostic of specific localities; observation of pleochroism, fluorescence patterns, and other optical features.

Position in the laboratory market

The SZX is positioned at the upper end of the stereo microscope market, with prices reflecting the optical quality and the modular accessory system. Competitors at this level include the Leica M-series and Zeiss Stemi series, both of which are also widely used in gem laboratory contexts. The choice between the major brands often reflects laboratory tradition and existing accessory infrastructure rather than fundamental capability differences; an experienced gemmologist can produce excellent work on any of the major premium stereo systems.

For routine gemmological practice, lower-priced stereo microscopes — including some Olympus offerings below the SZX line — are entirely adequate. The SZX class is appropriate where high-resolution photomicrography for publication or laboratory reports is required, where the laboratory needs the modular illumination accessories for specialised inclusion work, or where the workflow integrates with the broader Olympus or Evident ecosystem. The Evident Corporation continues to support and develop the SZX line under the new ownership, with current models continuing the design lineage of the earlier Olympus instruments.

Further reading

• Evident Corporation — microscopy products
• GIA Gems & Gemology — laboratory instrumentation
• Gübelin Gem Lab — Photoatlas of Inclusions