Tools
The darkfield loupe is an almost indispensable instrument. Indeed, it is sometimes difficult to correctly manage the lighting on the field and most of the clues to identify gems or their treatment are inclusions. In fact, if you cannot afford a gemological microscope for more than € 1,500, the darkfield loupe is an excellent alternative.
How does a darkfield loupe work? We have on one side the magnifying glass composed of a lens with a reflection system that prevents glare and on the other side the flashlight. The magnification is generally 10X. The lens should have the same characteristics as the gemologist’s loupe and be both achromatic and aplanatic. The stone is placed between the lens and the reflection system, through the side slit visible in the photo above. The use of tweezers is essential.
This instrument makes it possible to illuminate the inclusions while keeping the background dark. The inclusions stand out strongly which allows their identification. This magnifier is perfect for spotting halo inclusions around a small crystal, often present after heat treatment.
As with the gemologist loupe, we bring the lens of the darkfield loupe to the eye. We then move the stone back and forth to focus more or less deeply in the stone.
In terms of price, again you have to choose a quality instrument. They are found from $50 to $100. Here is the model that I have been using for years. I paid around $50 for it on their site.
To go further
- gemologist’s loupe
- lighting
- tweezers
- the polariscope
- the dichroscope
- the spectroscope
- Chelsea filter and other filters
- the refractometer
- the microscope
- UV lamp
- the carat balance