About

In the early twentieth century, an appraiser for Tiffany’s declared the Yogo® Sapphires to be “the finest precious gemstones ever found in the United States.”

“Yogo” is a trademark and the brand name for sapphires mined from Roncor, Inc.’s, properties.

The Kunisaki family has and continues to play a very important part in the mining and marketing of Montana Yogo® Sapphires.

In the early 1970s Chikara Kunisaki, owner and President of the mining operation built a 3,000 foot tunnel  which became known as the Kunisaki Tunnel.  The tunnel exists to this day and is under evaluation for commercial production.

An estimated 190,000,000 carats have been produced from Yogo Gulch since 1906.  In 1992, an 11-carat rough sapphire was discovered.

Today, Roncor has a strategic alliance with the mining company authorized to operate on its property, to obtain sapphires from Roncor’s property to manufacture and sell fine jewelry to the public.