Polariscope Guide, Part 1: Testing Gemstone Refraction

Buying a Polariscope

A polariscope is an inexpensive tool and an essential investment for the gemology student. Read our polariscope review to get a sense of what’s available. You can purchase a polariscope through Amazon or eBay or make one yourself if you follow the instructions below.

Even if you purchase a polariscope, knowing how to assemble one will help you understand how the instrument works.

Build Your Own Polariscope

A polariscope consists of three elements: a light source and two pieces of polarizing material, one fixed and one rotating.

Almost any light source will do, including good flashlights and desk lamps. Some designs use mirrors to reflect light into the polariscope, eliminating the need for a separate light source.

For high-quality polarizing filters, look for those designed for photography. For something quick and inexpensive, you can even use lenses from an old pair of sunglasses.

Types of Polarizing Filters

There are two types of polarizing filters: linear and circular. The linear type is easier to use. However, both types will work.

If you don’t know which you have, put two filters together. Then, hold them up to the light, look through them, and rotate one. The light…