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Forums Home » Reply To: Paraiba or Copper Bearing Tourmaline, How can I know?

Reply To: Paraiba or Copper Bearing Tourmaline, How can I know?

#177963
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gemguy
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You would need to send it a lab with proper experience. IGS uses a lab partner that is equivalently equipped to the GIA laboratory (full suite of equipment, including raman spectroscopy). The equipment required to accurately detect copper at Paraiba-level concentrations is extremely expensive, and requires operator expertise. If the question is whether a GIA Certificate or an IGS Certificate is more universally recognized, GIA is clearly more recognized. It is also much more expensive for larger-sized stones, and they charge you additional money for an opinion of origin. The IGS certificate is far less expensive, and uses a comparably equipped lab. Most people who intend to certify their stones to sell them send them to IGS for an ID report (no picture) to know what they have before they go buy the very expensive cert not knowing how it will turn out. If you spend the money to get the cert, and it doesn’t come back copper-bearing, you are out a lot more than the $55 you pay to get a positive ID. For folks who just want to know exactly what they have in their collections, those folks typically get a printed cert.

Using magnets to identify Cuprian Tourmaline? Unfortunately no, magnets won’t work. The amount of copper impurities in allochromatic tourmaline is generally very low. Concentrations as low as .05% by weight are relatively standard fare, and the highest concentration remains about 2.5%. At these levels, it is highly unlikely that copper in Paraiba Tourmalines would be detected with any magnet, except perhaps at the very highest concentration, and even then, not reliably so.

Also — Copper ions (Cu2+) have only one unpaired electron, and are not that magnetic to begin with. There is sometimes a strong magnetic attraction found in allochromatic Paraiba Tourmalines but it is likely due to the manganese content, not the copper. In Paraibas, manganese is often present in much higher concentrations than copper (up to 6.1% manganese oxide by weight). Iron is also found only as a trace element in Paraiba Tourmalines, but again, it is found at such an extremely low level of iron is not magnetically detectable.

Regardless…. even if it was magnetic, there are too many confounding trace elements for a novice with a basic spectrometer to reliably assign a “Paraiba” designation based solely upon magnetic reactivity or lack thereof.


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