The story begins with much excitement. The gem, named Teodora, was found in Brazil and cut in India, before being sold to rare gems dealer Reagan Reaney in Calgary – but there are doubts over whether it is in fact a true emerald.

‘I’m positive it contains emerald but I’m not sure how much of it is emerald,’ Jeff Nechka, the gemologist who appraised the stone.

 Nechka said that he cannot even confirm that the stone is in fact the ‘world’s largest emerald’. The stone has been dyed so Nechka says it is possible that at least part of it could be dyed white beryl – the mineral that makes up an emerald. ‘It has been dyed to some extent but it’s impossible to tell the intensity of the stone prior. It’s impossible to know how much of it is emerald.’

Director of Gemological Institute of America’s West Coast Identification Service, Shane McClure, said he had not examined the stone but that if there is any white beryl in the stone, GIA would likely term it ‘beryl with zones of emerald.’

 ‘We probably would not call it emerald no matter what,’. ‘They seem to think there is indication of natural green coloration but we wouldn’t call it emerald in any case.’

When experts grade an emerald color is by far their most important consideration with clarity coming in a close second.

Regan Reaney, the Calgary gem wholesaler who is selling the stone, despite stating that “anyone who questions the stone is welcome to examine it”, was arrested for fraud. His arrest stopped the emerald from being auctioned on. He pleaded guilty on those charges a few weeks later. Six years have pasted and it’s safe to say that if the gemstone was in fact genuine, you would have heard about it by now.

 Emeralds – the birthstone for the month of May – get their green coloring from the presence of chromium within the stone and the effect it has on constituent mineral beryl.

Unlike diamonds they are graded by eye. If when examined by the naked eye an emerald appears free from material trapped while it was being formed then it can be considered flawless.

Emerald crystals, like all other naturally occurring gemstone crystals, grow one molecule at a time meaning it takes prolonged periods to create a quality gemstone.

The emeralds being mined today are relics from the geologic events that took place hundreds of millions of years ago deep within the Earth’s crust.

And since they are expensive there are techniques to create synthetic emeralds. These fakes can be ‘grown’ in a laboratory by coating colorless beryl with an emerald overgrowth.

Emeralds can be found from as far afield as Columbia to Afghanistan, Zimbabwe, Brazil and Canada.