Difficult Gemstone Separations


Step 3: Practical Gemology

Lesson 27

One of the most difficult separations for a gemologist to make is between scapolite and citrine. “Scapolite, mica var. phlogopite” by Géry Parent is licensed under CC By-ND 2.0
One of the most difficult gemstone separations for a gemologist to make is between scapolites and citrines. “Scapolite, mica var. phlogopite” by Géry Parent is licensed under CC By-ND 2.0

While some gems are fairly easy to distinguish, others present greater challenges to gemologists. Two of the most difficult gemstone separations to make are scapolite from citrine and apatite from tourmaline. The good news is there are tricks to telling them apart. Both separations begin with a thorough examination.

Scapolite and Citrine

Say you were given a light yellow gem to examine. Your basic refractive index (RI) test yielded two readings on the table 90 degrees apart. The results were 1.545 and 1.552. A polariscope reading tells you the stone is uniaxial.

You enter this information in Gemology Tools Pro: color, yellow; optic …

Premium Article

This is a Premium Article. Please become a member to read this entire article and gain access to hundreds more like it.

Membership options