Fans of the US version of Antiques Roadshow on PBS learned a lot about "Kashmir" sapphires during a fascinating episode that originally aired in May of last year. It's an episode well worth revisiting as we celebrate September's official birthstone.

Filmed on the grounds of the Shelburne Museum in rustic Shelburne, VT, the highlight of Season 27 Episode 15 was appraiser Lucy Grogan Edwards' assessment of an Edwardian-period sapphire-and-diamond ring that was originally owned by the guest's great-great-grandmother, who died in 1912.

Edwards told the guest that when she first inspected the sapphire her "eyes lit up" because the stone was likely sourced in the Kashmir region of northern India.

The Boston-based appraiser explained that the platinum ring with milgrain details, Old-European-Cut diamond side stones and sapphire center stone was purchased circa 1900, a time when most sapphires were sourced in either Burma (now Myanmar) or Kashmir.

"When we're appraising sapphires, we're most concerned and interested in their origin," she told the guest.

She explained that Kashmir sapphires are considered to be the most beautiful, perfect standard sapphire that you could have in a piece of jewelry. She also outlined why Kashmir sapphires are so rare.

"In 1880, there was a landslide in the Kashmir region of India, and that landslide revealed sapphire deposits," she said. "The sapphires that were coming out of this area were the most beautiful in their color and their depth and their quality. So the maharaja of India at the time very quickly claimed that region for himself."

However, overmining during the period from 1882 to 1887 left that area completely depleted of sapphires.

"So every Kashmir sapphire that we see today came out of the ground in the Kashmir region of India in that five-year period," she said. "So they are very rare and spectacular in their quality."

Although Edwards' professional hunch is that the sapphire originated in Kashmir, she affirmed that the only way to really determine the origin of a sapphire is to have it tested at a gem lab.

Edwards told the guest that if her great-great-grandmother's ring held a Burmese sapphire — which is also a very beautiful stone — the ring would be valued at $40,000 to $60,000.

"And if it is, indeed, a Kashmir sapphire, which I feel pretty confident it is, at auction, I think we're looking at somewhere between $100,000 and $150,000," she told the shocked guest.

"That's quite something," the guest responded. "Thank you so much, I don't know what else to say."

"Well, I think we have your great-great-grandmother to thank for her exquisite taste," said Edwards, who added that she can count on one hand the number of Kashmir sapphires she has seen during her career.

"I hope that you do continue to wear it, because a sapphire like this really does deserve to be seen," said Edwards.

"Yes, it does," the guest agreed.

You can check out the full episode at this link…

Credits: Screen captures via pbs.org.