What does a dichroscope measure?
A dichroscope is a pocket instrument used in the field of gemology, and can be used to test transparent gemstones (crystals). Experienced gemologists, observing the pleochroism of some gems, can successfully detect gemstones from other artificial stones using this instrument.
Which lens is used for testing gems?
Gemologists prefer the hand loupe. For gemologists, the 10X loupe (with ten-power magnification) is the standard for hand-held gem identification. Although you’ll find more powerful loupes, the depth of field (the area that’s in focus) is so small above 10X that they’re hard to use.
What is a Polariscope used for?
The polariscope is an optical inspection device used to detect internal stresses in glass and other transparent materials such as plastics, synthetic resins, etc. A polariscope is composed chiefly of a light source and two crossed polarized lenses such as Polaroid {{Registered Trademark}}.
What is a gemstone refractometer?
A Gemological Refractometer is your primary and most powerful tool in gemstone identification. As with any typical critical angle refractometer, it will measure the Refractive Index of faceted stones, transparent to near opaque, whether loose or mounted (in many cases), up to an R. I. value of 1.81.
What tools are needed for gem mining?
This kind of prospecting is hard labor and requires a rock hammer, shovel and bucket. Pickaxes are used for breaking up hard ground and getting into crevices in the rocks. Miners use scrapers made from iron straps and fencing wire help to remove dirt or small gems from crevices.
What does a Chelsea filter do?
A Chelsea Filter is a dichromatic optical filter, meaning that it allows transmission of only 2 colors of light: deep-red wavelengths around 690 nanometers and yellow-green wavelengths around 570 nanometers. These match emerald’s emission and absorption properties.
What is a gem polariscope?
The GIA Polariscope is used to test the optical properties of gemstones and determine whether a stone is singly refractive, doubly refractive or is an aggregate. Doubly refractive stones may be divided further as to whether they are uniaxial or biaxial.