- Measures a compact 1⅝ inches in length and ⅝ inch in diameter.
- Fixed focus for rapid differentiation.
- Designed with hexagonal head to avoid rolling.
The dichroscope provides one of the fastest, easiest ways for differentiating transparent stones of the same color from one another. Using this instrument, you can easily distinguish a ruby from a red garnet or a red spinel (one of the popular “new” stones seen with increasing frequency), a blue sapphire from fine tanzanite or blue spinel, an amethyst from purple glass, or an emerald from many imitations and look-alikes.
We recommend a calcite type (not a polarizing type). It is a small tubular-shaped instrument approximately two inches long and one-half inch in diameter. When you look into a dichroscope you will see two small rectangular windows at the opposite end. When colored stones are viewed with the dichroscope, some will show the same color in both rectangular windows, while other stones will show two colors or two different tones or shades of the same color. Here’s how it works....
When a ray of light enters a colored gemstone, depending on the particular properties of that stone, it will either continue traveling through as a single ray or divide into two rays. Stones through which it continues as a single ray are said to be “single refracting”; stones through which it splits and travels as two rays are “double refracting.” We call these stones “dichroic” (di = 2; chro = color). Some stones show three colors when viewed with the dichroscope. We call these trichroic (tri = 3; chro = color). These stones are also double refracting but when a light enters from certain directions we get one pair of rays (traveling at certain angles and speeds); when it enters from another direction, we get a different pair. In the second pair, one of the two rays will travel at a different angle and speed from either of the two rays in the first pair. Thus the third color.