Cutting for Color

Opal creations with Jim Donovan

Published online: Sep 17, 2021 Articles, Education And Arts, Lifestyle Steve Smede
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If you only know Jim Donovan from his day job, you might picture him running a large-format printer or clicking and dragging his color-correction tools across a digital media landscape. 

For those who know him best, however, Donovan’s landscape of choice is an undisclosed rock quarry 63 miles north of Idaho Falls.

It is here that the Eastern Idaho print-color specialist pursues his passion for prospecting and ultimately procuring one of nature’s most fascinating gemstones: the famous Spencer opal.

Jim is just one of a select few professional gemstone cutters who specialize in the creation of custom opal jewelry—the end product of unique precious mineral deposits found near the Clark County hamlet of Spencer.

“I started opal mining just on a whim,” he said. “I had driven by Spencer many times and saw the sign, ‘America’s opal.’…From the first opal I picked up, I was hooked.”

After repeated visits to the quarry over the years, Jim eventually started asking resident opal experts about the process of cutting stones and turning them into a finished product.

“Eventually I got my own equipment. Paid cash for it, and just started cutting my own stones,” he said. “I made a bunch of anybody does when they start doing something.”

Countless training runs later, Jim decided to take his budding skillset to the next level.

“One thing I noticed when I went up to the mine at Spencer is that people would come from all over the world to mine because it is very unique. It is the most beautiful opal on earth,” he said. 

According to a description from Spencer Opal Mines, the formation that makes up the opal comes from a melting pot of geologic processes—namely a flow of rhyolite and obsidian that is full of gas pockets, plus a secondary deposit of silica that is ferried along by underground carried by geyser activity.

“From there, it forms into very thin bands. Most of it has to be cut into what’s called a triplet,” Jim said. “It’s not a traditional way to cut stones. You have to use several different materials. It’s a long process, and it takes a long time to learn how to do it.”

For a deeper dive, the Spencer Opal Mines website has all the technical details. Here’s the gist:

To make a triplet, the opal is ground perfectly flat parallel to the fire layer until the intense fire shows completely across the surface. Then a flat piece of black basinite or obsidian is epoxied to the flat fire layer. The opal is again ground flat on the opposite side until the fire layer is exposed and shows its greatest intensity against the black background. At this time the opal should be about the thickness of a hair. A crystal cap is applied with epoxy and the opal is ground to its final shape. Thus, an Idaho Opal Triplet is created.

After Jim had cut hundreds of his own stones, he noticed that most of his fellow prospectors had no clue how to even begin the process. Fortunately, he had already become good friends with the owners of the mine over the years. 

“I asked them if they would mind if I took peoples’ material and cut their stones for them. They said, ‘Go for it,’ so I formed my own business, and we just had a symbiotic relationship,” he said. “There was no money that changed hands. People just knew if they went there, they had the ability to get their stones cut for them.” 

Although the original mine is now closed to the public, there is a secondary location—right next to the Spencer Opal Mines store and cafe—where the raw mine material is transported and dispersed for visitors to try their hand at prospecting.

“It’s been a really interesting experience,” Jim said. “It’s really become a passion.” 

For our interview at his home-based shop in Ammon, Jim went on to describe his process and the tools at his disposal—an arsenal of machinery ranging from basic grinding wheels, cutting saws and crafting tools to more specialized contraptions like a “flat-lap” wheel and “cabochon” machine.

True to its name, the opal triplet in its completed form has three layers. 

The bottom one consists of black basalt, which helps to reflect the opal’s radiant hues. The middle layer is an ultra-thin slice of the opal itself. On top sits a quartz cap, which slightly magnifies the opal underneath it and protects the opal from damage. According to the experts at Spencer Opal Mines, the quartz is extremely durable. And should the cap become scuffed or hazy after years of use, the top surface can be easily polished.

From an adjacent tray of raw materials, Jim held up a chunk of dull, nondescript rock, then replaced it in his hand with a finished stone. The transformation of the former to the latter was nothing short of jarring.

“It’s an amazing thing,” he said. “To find a stone, something that has color in it...and then, through the magic of machines and ability, I can turn it into something that looks like that.”

He marveled at the colors as he spun the finished triplet at the end of a dowel pin.

“Gaia’s artwork,” he added. “Mother Nature’s amazing. She formed it.

I just blew the dust off.” 

CJ’s Opals-N-AT

208-522-8191 •

Retreat for Rockhounds

Ever dream of digging up a precious stone at the local quarry and having it made into a beautiful piece of jewelry? The “thrill of the find” is easier to accomplish than you might think.

World-famous opal deposits exist right here in the Greater Yellowstone Country, including a motherlode just north of Idaho Falls in Spencer.

The primary mine is now off-limits for public access, but the owners have also established a “mini mine” for area rockhounds. Spencer Opal Mines can be found right off the freeway in Spencer. It’s hard to miss, especially when the mini mine is bustling with recreational prospectors.

Call 208-374-5476 for details, or visit

Opals are Out of this World

Idaho is an opal-rich area of the Earth, but Earth is not the only planet opals call “home.” In 2008, opals were discovered on Mars. Because opals need water to form, the presence of opals provided evidence that Mars may have had liquid surface water for billions of years.

To read more of the September issue click here.


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