• This tool is of a Generic Heavy Duty metal tube measures a compact approx 45 mm in length and 15 mm in diameter.

• Fixed focus for instant differentiation.

• Designed with light weight (18.5 grams ) for ease of use.

Calcite Dichroscope

Calcite dichroscope is a handheld important pocket tool which works on principals of optical properties for viewing the different colors or shades of a pleochroic piece of rough / faceted gemstones. This makes it an essential part of any gemologist's or lapidary's basic gemology toolkit. Shows whether or not a stone is dichroic (reflects two colors). It is also a very important tool for the students learning geology / gemology.
Made with calcite for long lasting use. Protective plastic case included.

Calcite dichroscope provides one of the fastest and easiest method for differentiating transparent stones of the similar color from the another. Using it, one can easily distinguish a Ruby gemstone from its simulant a red Garnet or a red Spinel (one of the popular “simulant" stones seen ), Typically, a garnet will just look red in both windows when viewed through a dichroscope whereas Ruby will show two different shades in two different window. A blue sapphire gemstone from fine blue Spinel or a Tanzanite gemstone, an amethyst from purple glass, or an emerald from many imitations and look-alike commonly sold in the market.

We normally recommend a calcite type (not a polarizing dichroscope). It is a small tubular-shaped pocket friendly most important instrument for the gemstone identification. Approximately 45 mm in length and 15 mm in diameter. When you look through a dichroscope you will see two small round overlapping or closely connected windows at the opposite end. When colored transparent rough / faceted gemstones are viewed through the dichroscope, some will show the same color in both round windows, while few may show two colors or two different tones or shades of the same color.

Here’s how a calcite dichroscope works....

When a single ray of light enters a colored gemstone, depending on the optical properties of that stone, it will either continue traveling through as a single ray or get divided into two rays.
Stones through which it continues as a single ray are identified as “single refracting”; stones
and while other gemstones wherein it splits and travels as two rays are “double refracting.” These stones are identified as “dichroic” (di = two; & chro = color).

Some stones exhibits three colors when viewed with the dichroscope at different directions. These stones are identified as 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 specific angles and variation in speeds); while when it enters from any another direction, it exhibits a different pair of colors / tones . In the second condition, one of the two rays will travel at a different angle and speed from either of the two rays in the first place. Thus it exhibits the third color.

It’s advisable to carry a dichroscope with you at gem shows. A piece of garnet or a glass is a lot cheaper than a piece of ruby, and it’s not uncommon for them to get mixed knowingly or accidentally. They are often found in the same geographical areas and mines. (Identifying the stones in rough parcels could be bit difficult). Dichroscope can’t eliminate all possibilities of , but they do help in making instant eliminations when one can’t perform complete through examinations.

Here is a quick list of Common Gem stones And its Dichroism

Andalusite – Yes (trichroic)

Apatite – Yes, weak

Axinite – Yes, Strong

Beryl – Yes, but usually weak

Chrysoberyl – Yes, but usually weak

Danburite – Yes, weak

Diopside – Yes, weak

Garnet – No (occasionally a color change garnet will show an anomaly)

Iolite – Yes

Kyanite – Yes (Strong)

Opal – No

Orthoclase – No

Peridot – Yes, but very weak Quartz – No

Ruby/Sapphire – Yes

Scapolite – Yes

Spinel – No (ADR)

Sphene – Yes

Spodumene – Yes (kunzite, hiddenite…)

Tanzanite – Yes (Strong)

Tourmaline – Yes

Topaz – Yes

Zircon – Yes

for more technical details : CLICK HERE

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