A gemological microscope is a stereo microscope adapted for examining loose and mounted stones. The key differences are a darkfield base that illuminates the stone from below at an angle, a rotating stage, and a long working distance that leaves room for tweezers and a stone holder.
Yikmo builds gemological stereo microscopes with 0.67×–4.5× zoom, trinocular heads for photography and 0–325° rotating bases.
In brightfield, light passes straight through the stone and the internal inclusions are washed out by the bright background. In darkfield, light enters the stone from the side and is reflected internally; inclusions scatter it and appear bright against a dark field.
This is why almost every diamond grading bench uses a darkfield base. It reveals internal graining, crystals, feathers and pinpoints that are invisible in transmitted brightfield.
| Illumination | Darkfield for internal features; reflected light for surface; transmitted brightfield for colour and transparency. |
|---|---|
| Zoom | 0.67×–4.5× covers overview through to inclusion detail; 10× to 40× total is the working range for grading. |
| Working distance | At least 100 mm so tweezers and a stone holder fit under the objective. |
| Photography | A trinocular head with a C-mount camera lets you document inclusions for reports and certificates. |
Yes. Internal inclusions in a brilliant-cut diamond are best seen with darkfield illumination, which is why grading laboratories use it as standard.
Yes, with a trinocular head and a camera adapter. A 0.5× adapter is usually used so the full field of view is captured.
100 mm or more, so that tweezers, a stone holder or a grading tray can be placed under the objective.
Send us the material and what you need to measure. We reply within one business day with a specification and quotation.
