Emerald Myth Busters: Identifying Colombian Stones

Emerald Myth #1: Colombian emeralds are colored by chromium. Zambian are colored by vanadium.

Chromium (Cr), vanadium (V), and iron (Fe) are the known chromophores for emerald. Colombian emeralds typically feature very low percentages of Fe and moderate to high percentages of both Cr and V. It's not unusual for the V percentage to exceed that of the Cr in Colombian emeralds. Zambian emeralds typically have higher Cr and Fe, and lower V, than Colombian.

Emeralds from Sandawana, Zimbabwe have medium to high Cr and very low V. The most abundant chromophore in emeralds from Fazenda Bonfim, Brazil is Cr, while its V is consistently low.

Brazilian, Zambian, and Zimbabwean emeralds typically have a Cr content 10-20 times higher than V content.

Emerald Myth #2: Three-phase inclusions indicate Colombian origin.

Three-phase inclusions with gas, liquid, and an included crystal also occur in emeralds from Afghanistan, Brazil, China, Ethiopia, Nigeria, Russia, and Zambia.

Emerald Myth #3: Pyrite inclusions indicate Colombian origin.

Pyrite inclusions also occur in emeralds from Afghanistan, Austria, Brazil, Madagascar, Norway, the United States (North Carolina), and Zambia.

Emerald Myth #4: A Chelsea filter can help separate Colombian emeralds from those with other origins.

Fe dampens the Chelsea filter reaction induced by Cr. As a result, many emeralds from Brazil, Zambia, Ethiopia, and other sources with high enough Cr and relatively high Fe will show no reaction. On the other hand, emeralds with sufficient Cr and low enough Fe will show a pink to red Chelsea filter reaction, typical of Colombian emeralds. However, this has also been observed in some emeralds from Afghanistan, Brazil, China, Egypt, Ethiopia, Pakistan, Russia, Zambia, and Zimbabwe.