Asking the co-owners of Crystallize, a rare gemstone store new to Roslyn, to pick their favorite crystal is like asking a parent to choose their favorite child.

When asked to pick a favorite, business partners Alex Amiel, 31, and Ian Lopez, 34, sighed and ran their hands across their faces, calling it a “really tough” decision.

“They’re all really special and unique and hand-selected,” Amiel said. “I could tell you a whole story about every single one.”

Large glass cases lit by tiny bulbs line one store wall. Their shelves are packed to the brim with special finds, from a perfect pink crystal sphere to large chunks of crystallized amethyst.

Amiel and Lopez, both experts in the gemstone trade field, have spent years building their joint collection. But their careers in gemstone trading began innocently enough – with juvenile rock collections and a business class in college.

Both Amiel and Lopez were raised in Westchester. Amiel began collecting rocks and gemstones when he was 15. And when Lopez moved out on his own as a young adult, he bought small gemstones and rocks to decorate his place.

The two met as young men at SUNY Westchester Community College in an entrepreneurship class. Their task? To pitch an original business plan.

Amiel crafted a plan to work as a gemstone trader, buying and selling rare finds at crystal trade shows, and presented his pitch to the class.

“We sort of had talked about it. Investing some money into it. What’s the limit? How far can we go from this?” Lopez said. “It became much more and more serious as time went on.”

That class assignment led to successful careers in gemstone trading for Amiel and Lopez, who travel the world to attend the biggest trade shows – from Tucson, Ariz., Springfield, Mass., and Denver, Colo., to as far away as Germany.

“People just don’t understand that this [industry] even exists,” Amiel said, “because people have been doing it for a very long time. But the majority of people think it’s either a museum thing or crystals are for jewelry, but these are all individual little pieces of art that grew in the ground.”

Buying and selling crystals is one of the oldest trades in existence, according to the business partners. The Vanderbilt family were well-known gemstone collectors as well as J.P. Morgan, the namesake of morganite, Lopez said.

Amiel and Lopez have dedicated their careers to the gemstone trade industry, studying up on industry knowledge, forming connections with mine owners and building a social media presence including more than 40,000 followers on Instagram.

But when Amiel and Lopez weren’t attending trade shows, their precious rocks just sat in boxes. The co-owners decided they needed a flagship gallery to display their collection and the Roslyn storefront was the perfect fit.

“It’s beautiful. An old, historic village,” Lopez said. “It’s safe and it’s a great place.”

The storefront at 19 Main St. includes a small viewing and shopping area and an office in the back.

Crystallize offers a range of items for sale, from valuable collectors’ items valued at tens of thousands of dollars to small affordable rocks to keep on a desk.

One special find is a large American mineral located at the very front of the store. The massive orange crystal is a calcite specimen, with metallic chunks of sphalerite attached to the bottom of the crystal.

The calcite hails from the Elmwood Mine in Tennessee, a zinc mine opened for a commercial mining project that is now closed, the store owners said. Any gemstones excavated from the mine were snuck out, since miners were not allowed to remove the gemstones, Amiel and Lopez said.

The calcite is one of these so-called “lunchbox specimens,” since miners would literally use their lunchboxes to sneak crystals out from the work site. But it is a wonder how this specimen was removed from the mine.

Crystals are sized according to the cabinet required, from small cabinet to large cabinet. The calcite specimen at Crystallize is museum-sized, the owners said. An incredibly rare find with little to no damage and near impossible to replace, the calcite is valued at $65,000, the owners said.

Other standouts include a large hunk of purple, blue and gold fluorite from the Annabel Lee Mine in Illinois and a huge slab of crystallized amethyst shaded in hues of lilac and dark purple.

Despite these crystals’ beauty, Amiel and Lopez said the art of collecting has declined over the years, perhaps making the Crystallize storefront just as rare a find as the stones it houses.

“When I was a kid, people were collecting Pokemon cards and action figures and pogs [milk caps] and all different stuff, and nowadays with kids it’s all digital,” Amiel said.

The store owners said they welcome all kinds of customers to their store, from educated traders to homeowners shopping for a new decoration to those who just want to admire the collection.

Crystallize will be hosting a grand opening June 30 from 12 p.m. to 6 p.m. in collaboration with Pietro’s next door.