Pomonas is a copper-bearing tourmaline locality in Edo State, Nigeria, brought to the trade in the early 2000s and significant for its role in extending the geographical scope of what the international coloured-stone market now describes as Paraíba-type tourmaline. Pomonas material exhibits the diagnostic blue-to-green hues caused by trace copper and manganese, and the deposit sits alongside Brazilian and Mozambican production within the broader cuprian elbaite category as defined by the major laboratories.

Discovery and the cuprian elbaite category

Cuprian elbaite was first identified in commercial quantity at São José da Batalha in the Brazilian state of Paraíba in 1989, and for roughly a decade was understood as a Brazilian phenomenon. The recognition that copper- and manganese-bearing elbaite occurs elsewhere — first in other Brazilian states, then in Nigeria from the late 1990s and early 2000s, and subsequently in Mozambique — forced the trade and the laboratories to reconsider how the name Paraíba should be applied.

Pomonas was among the Nigerian sources that brought this question to a head. Material recovered from the Edo State deposit and adjacent localities showed the same defining trace-element signature — copper and manganese above background levels — as Brazilian Paraíba, and produced a comparable range of saturated blue-to-green colours. The Laboratory Manual Harmonisation Committee (LMHC) eventually issued guidance that the name Paraíba may be applied as a varietal term to copper-bearing elbaite regardless of geographical origin, while origin determination remains separate and is reported on the laboratory document.

Material characteristics

Pomonas tourmaline typically exhibits hues from neon turquoise through saturated greens, with some material showing a more violet-blue cast than the classic Brazilian palette. Saturation tends to be slightly lower than the finest São José da Batalha production, though the upper end of Pomonas output overlaps with mid-grade Brazilian and Mozambican material in colour appearance. Clarity is variable; well-recovered Pomonas can be eye-clean in commercial sizes, while heavily included material is more common.

Trace-element analysis by laboratories including GIA and Gübelin has established the elemental fingerprints that distinguish Nigerian, Brazilian, and Mozambican production. Copper, manganese, and the lanthanide-series trace pattern, together with characteristic inclusion suites, allow origin attribution in most cases, though the laboratories remain conservative where the data permit multiple interpretations.

Treatment and identification

As with all cuprian elbaite, heat treatment is routine and is reported on laboratory documents. Heating drives off the manganese-induced reddish component and shifts the colour toward the desirable neon blue-to-green range. Identification of the species is straightforward by refractive index, specific gravity, and ultraviolet-visible-near-infrared spectroscopy showing the diagnostic copper absorption. Origin attribution to Pomonas or to Nigeria more broadly relies on the trace-element work conducted at the major laboratories.

In the trade

Pomonas and other Nigerian copper tourmalines trade at a discount to fine Brazilian Paraíba but at a premium to copper-bearing material from less-recognised localities. The market distinction is meaningful: a stone with a Brazilian-origin opinion from a major laboratory typically commands a multiple of the per-carat price of an otherwise comparable Nigerian stone. For buyers, the practical guidance is to commission origin documentation from a recognised laboratory before paying a Paraíba-tier price, and to read the report's origin language carefully.

Further reading

• GIA Gems & Gemology — cuprian elbaite from Nigeria and Mozambique
• ICA — Paraíba tourmaline reference and trade definitions
• International Gem Society — tourmaline mineralogy and identification