The usage of the loupe or hand lens is not there to replace classic or conventional gemological instruments. Although with the right knowledge and work structure in several cases it can lead to a correct diagnosis, but don’t forget it might require some years of practice. When you cannot find enough diagnostic features to determine the gemstone, it can speed up your overall workflow and reveal some indicative features. Therefore observe every gemstone over and over with your loupe/hand lens to gain practical experience.
Before You Start
- Clean the gemstone thoroughly, remove all external fingerprints and remove dust particles with chamois leather. Once this is done, don’t touch the gemstone with your hands again, only use approved gemological tweezers to prevent causing damage to the gemstone.
- Use a daylight illumination at 5500K and always use the same.
- Use an achromatic loupe and verify it doesn’t have spherical aberration.
- Place yourself in a comfortable and correct body posture.
- Always work with the same consistent work structure.
Through years of research the following work structure showed to be effective.
When you are determining gemstones with a loupe, a different mindset is necessary, as you can’t rely on any measurements. Here you entirely depend on your stock knowledge of specific “VISUAL” characteristics of certain gemstones, skill and your vision. Gemological identification tables are rather based on measurements achieved through research with gemological instruments and not based on visual characteristics of gemstones. For this reason it is important to summarize all the most important visual characteristics and create your own gemstone identification tables for loupe use. Such a procedure is ongoing, requires time and patience but will improve your gemological knowledge by far. It’s understandable that it becomes very hard to impossible to diagnosis colorless gemstones without inclusions.
As you are practicing gemology, the same rules apply. Be reminded of the important notice found under category: Gem Identification.