Millions of goods flow through Tucson during the gem show weeks: Beads. Pounds of amethyst. And dollars.

The Tucson Gem, Mineral & Fossil Showcase is underway, with about 40 shows at hotels and in temporary structures in parking lots convenient to the freeway. Shows have been running for the past week and will continue through mid-February, selling everything from geodes to dinosaur statues. Vendors and buyers come from around the globe to Tucson’s crown tourism jewel, pumping $120 million in direct spending into the local economy.

Ryan Johnson of North Carolina has been coming to Tucson for the last 25 years to get the materials he enjoys and needs as a collector, trader and craftsman. 

“It’s the biggest, just hands-down the largest,” stop on the circuit, he said.

A lapidary, Johnson held up thin agate slices to the light filtering into a tent near Kino Veterans Memorial Stadium on the southside. Enthusiasts look for characteristics like transparency, color and intriguing dendrites, where crystals form branching patterns that look like ferns or moss.

He said he planned to spend about $1,500 during this year’s trip— less than usual.

But business like that adds up.

According to a study commissioned by Visit Tucson, 47 percent of out-of-town buyers like Johnson spent at least $1,000 in on-site purchases in 2014. Overall, the $120 million that the shows under the gem show umbrella drew last year was a 20-percent increase from 2007, when it pulled in $100 million.

Spending is up in several categories, per the study’s sample of 1,000 attendees: 26 percent spent $3,000 or more on their Tucson trips in 2014, up from 16 percent in 2007; the average per-trip expenditure was $2,731 in 2014, compared to $1,878 in 2007. Seventy percent of international buyers spent more than $1,000 in on-site purchases, and close to half broke the $5,000 mark. Locals weren’t afraid to spend more 

than a couple bucks themselves, with 14 percent of local buyers spending at least $1,000.

Some of the shows have solid local roots. The Tucson Gem & Mineral Society’s show in the Tucson Convention Center – “the” show, and the show that started it all as a swap meet in an elementary school parking lot in 1955 – is run by the nonprofit earth science enthusiasts’ club. That one is Feb. 12-15, one of many in the downtown area. 

Alby Davis, who lives in Picture Rocks, organizes the Miners Co-op Rock Show in Marana. The show started a few years ago in Colorado, which also has an active gem and mineral show circuit, and came to the northwest side last year. With vendors numbering in the mid-20s last year and in the upper 30s this year, it’s already outgrowing its spot off Interstate 10 south of Orange Grove Road. 

Davis is a lifelong gem show attendee and a rockhound, one who harvests rocks and minerals from their natural environment. Keeping to that, the Miners Co-op show screens potential vendors to ensure they take their product straight from the ground themselves or are the artisans who create the finished wares. Davis, for his part, visits a private mine near western Arizona’s Colorado River called the Good Day Mine, where, with permission, he hunts gem silica, a gem that resembles turquoise (it gets its green-blue hue from copper).

As his show is a co-op, Davis, as the organizer, isn’t in it to profit, although the individual vendors do make money. He said the rockhounding emphasis lets vendors get back to their roots in a congenial atmosphere. 

The show is locally organized, but like other shows around town, hosts sellers from around the world.

“We have miners from Mali, we have miners from Morocco, we have miners from Switzerland in our show,” Davis said.

Davis said he has suggested to the town of Marana a municipal arts center that can house the rock show in the winter and host other events during other times of the year, an idea to which he said the town was receptive. 

On an overcast day the day before its Jan. 30 opening, the scene was already hopping at the co-op’s open-air Travel Center Drive location in anticipation.

Davis said shoppers like specific and unusual items and they know the rockhounds will have them.

 “We have unique products. We go out and we mine in unique areas and we find unique things. They come looking for that,” he said. “A lot of jewelers come looking for that, a lot of carvers come looking for that, a lot of people that just want a piece of rock that’s different coming looking for it.”