Sapphires are the official Montana state gem, but one type of sapphire in particular stands out: the Yogo sapphire.

Roberts Yogo Mine in central Montana is the only commercial Yogo mine in the world, and a new group is helping to ensure that the process of getting the gems from the mine to the store is done responsibly.

(via Google Maps - approximate location)

Mike Roberts, the new owner of Roberts Yogo Company, explained why he came to Montana from Alaska, where he mined for gold: "Just a new adventure to see, sounded like something fun to do, and hopefully there would be lots worth doing, (and) lots of money in it."

All it takes is following what Roberts calls the "yellow brick road," so named because limestone rock has a vein or dike running through it. The "road" runs hundreds of feet underground.

And about every 30 feet of any given vein, there are 10 carats of sapphires, considered by many to some of the best in the world.

But contrary to common belief, striking it rich isn't just a matter of luck. Roberts said: "None of it's luck. It's just the more dirt you move, the more sapphires you get."

In just a couple of years, they have already found some 100,000 carats.

The underground ore, ladened with sapphires, is loaded up and taken back to the surface. It's then sorted and the water washes away the ore.

Yogos are considered more valuable because they are natural and untreated, unlike other sapphires, but they tend to be small.

And after being mined, they get cut and shipped to stores, and that process is the focus of a group called the Earth Solutions Committee. The group includes Roberts, area jewelers, gem cutters and environmentalists.

"The idea of conscionable mining is something that reaches across sectors," explained Committee representative Claire Baiz. "We are going to add value to the Yogo sapphire by demonstrating that it's socially responsible and environmentally ethical in the way we mine and cut and distribute and sell the Yogo sapphire."

The mine does not use chemicals and even outside observers seem impressed.

Stuart Levit of the Center For Science In Public Participation said, "As mining goes, (it's) probably as clean as you can ask for. However, ‘how clean' is clean is always a real big question."

Just one of the questions this group will try to answer in the effort to make the Yogo sapphire even more precious.