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Blue Topaz

Ana Collins studies the Chemical and Optical Discriminators for Texas Topaz.

Anna Collins
Anna Collins

I am currently working on a comparative analysis of Texas
and Brazilian topaz under Dr. Mark Helper. This project
arose as a result of Dr. Helper’s Gem and Gem Minerals class as the reason for the price difference between the topaz
from Texas and Brazil was continuously scrutinized. Texas topaz, both blue and colorless, is currently being sold for $100-150 per carat, whereas blue, treated Brazilian
topaz is being sold for $3-8 per carat.

Why the price difference? Besides the fact that Texas topaz is rare and our state gemstone, is there a way to quantify the differences between the topazes from the different localities?

Irradiated Brazilian topaz
Irradiated Brazilian topaz

Is there a geochemical or optical “fingerprint” that would allow us to identify the source of origin? I am using a variety of methods (i.e. X-ray diffraction, absorption spectra, electron microprobe, cathodoluminescence and LA-ICPMS) to create a suite of identifying characteristics with the goal of answering these questions.

If any differences are found it may have implications as to the value of Texas topaz as a gemstone.

Honors Advisor:

Dr. Mark Helper