Precious stone dealer
Vincent Renault, founder of Johya
A lifelong lover of precious stones, Vincent Renault trained in gemology before making stones his trade. He has been buying and selling precious stones for several years, and founded Johya.
He specializes in Colombian emerald: he lived in Colombia for several years, a country he holds dear and where he has kept his contacts.
At Johya, we buy our emeralds in Colombia, with no middleman: every stone is chosen in hand, on site. You pay for the stone, not the chain.
The travel notebook
Our buying trips to Colombia, written up as we go.
Further reading
Guides, country profiles and travel notes published on the site.
- The emerald's jardin: why its inclusions are proof of a natural stone
- Emerald Twinning: The Formations Collectors Look For
- Beryl: The Mineral Family of the Emerald
- The Muzo emerald museum: a visit inside
- Emerald on Silver: What a Handmade Colombian Piece Is Worth
- Emerald anniversary: 40 years of marriage
- Emerald Prices: The 7 Criteria That Set the Figure
- The Emerald, Birthstone of May
- How Much Does a 1-Carat Emerald Cost in 2026
- The emerald-cut diamond, what this shape really changes
- Ruby, sapphire or emerald: which one to choose?
- The cabochon emerald, a cut with its reasons
- Brazilian Emerald: Deposits, Color and Price
- Colombian Emeralds: The Complete Guide
- Australian Emerald
- Afghan Emeralds: The Forgotten Green of the Panjshir
- Zambian Emeralds: A Source That Now Matters
- Muzo, emerald capital of the world, seen from the inside
- Bogotá to Muzo, the Road That Leads to the Emeralds
