How to Use a Loupe for Gemstone Examination

Learn how to use a 10x loupe for gemstone examination. Discover what makes a good loupe, how to test lens quality, and the right technique for inspecting gems.

Loupe: Your First Tool in Gemstone Examination

When you examine a gemstone, your eyes are the starting point.
You notice:

• Color
• Luster (surface reflection)
• Condition
• Shape and possible identity

But to see deeper, you need magnification.
The standard tool is the 10x loupe.

Why 10x?

• It enlarges enough to reveal most internal and external features.
• Higher power (15x–25x) exists, but the focus becomes very narrow.
• The field of view gets smaller, and the working distance shortens.
• That makes them harder to use compared to 10x.

Why Triplet Loupes Are Better

Single-element lenses above 3x create problems:

• Image distortion
• Color fringing (colored edges around objects)

For gemstone and diamond work, you need triplet loupes.

• Built with 3 lenses.
• Corrected for distortion.
• Corrected for color fringing.

How to Test a Loupe Before Buying

Take a piece of graph paper. Look through the loupe and check:

• Focus: All lines should be clear at once.
• Distortion: Lines should stay straight. No curves or widening at the edges.
• Clarity: Lines should look sharp, without colored edges.

If the lines fail these tests, the loupe is not suitable for gemology.

Correct Technique: Using a Loupe with Cut Stones

How you hold your loupe and tweezers makes a difference.

• Hold the loupe close to your eye.
• Keep the stone steady with tweezers at the right distance.
• Move the stone, not the loupe, when examining inclusions.

This simple method gives you a stable and clear view.

Key Takeaway

A 10x triplet loupe is the gemologist’s trusted tool.
With the right technique and a high-quality lens, you can clearly see the inclusions and features that define a gemstone’s true identity.

A practical guide on using a 10x loupe for gemstone examination. Explains lens quality, distortion checks, and correct handling for spotting inclusions.