Partially due to the proprietary secrets and complexity involved, and partially due to marketing, Michael and Misato Mortara call their latest collection of abstract and sculptural glasswork the "Enigma" series. The unique techniques they use to create patterns in glass often prompt patrons to ask how they did it.

"That’s a really great thing for an artist," Michael Mortara said. "When people see a piece of your work and have to know how it comes about. They say, ‘How’s that even possible?’"

Mortara won’t provide many details about the process, yet three of his new works are featured at the 48th annual Hawai’i Craftsmen Statewide Juried Exhibition, where viewers can make an up-close examination. The exhibit runs through Nov. 20 at the Honolulu Museum of Art School. Classic fine arts, such as painting and photography, are discouraged in favor of art made from clay, stone, metal, wood, fiber and glass (or a combination of those materials).

Barbara Thompson, the exhibit’s program chairwoman, said 270 pieces of art were submitted for the show this year, from Oahu, Maui, Kauai and the Big Island, and 92 were selected for display. The organization incorporated a new computer submission system this year, and she said it boosted the participation and selection of young and emerging artists, who complement more established artists. This year they include Mortara, ceramist Joey Chiarello and woodworker Sharon Doughtie.

Thompson said the show’s juror — Lowery Stokes Sims, curator emerita of the Museum of Arts and Design in New York — noted the strength in the corpus of ceramics, but also that there were relatively few glasswork pieces. Thompson said that was something she noticed as well when she moved back to Hawaii recently and was taking stock of the arts community. She learned that glass artists here suffer not from a lack of creativity or talent but from a dearth of affordable and accessible facilities. The Mortaras are among the few who have been able to build and maintain a professional shop.

Michael Mortara learned to work with glass at Punahou School and met Misato in glass-blowing classes taught by professor Rick Mills at the University of Hawaii. Even though Michael studied architecture and Misato studied travel industry management, they eventually turned full time to indulge their love of glass art and moved to the Big Island to build a studio.

In addition to the pervasive tropical heat, Hawaii is inhospitable to glass artists for many reasons, Michael Mortara said. Glass has to be shipped here, and most of the finished pieces end up being sent back to the mainland, creating additional layers of costs. The cost of land, propane and electricity, all imperative elements for the operation to be efficient and successful, is expensive in Hawaii. Because of such challenges, the Big Island, Oahu and Maui have a smattering of glass galleries and shops compared to the rest of the country, especially the Northeast and the Pacific Northwest.

The 54-year-old Mortara left Oahu in 2000 to build a small studio on rainforest land near Kilauea. He and his wife of 21 years have since expanded into a second studio and gallery near the entrance to Hawai’i Volcanoes National Park. They call their operation 2400 Fahrenheit, a reference to the temperature needed for working with glass.

The Mortaras make their pieces through a subtractive approach, like sculpting. They start by creating what they describe as a geode of layered glass, stacking colors between clear layers of molten material. The block takes about three weeks to create, and then the artists spend another three weeks chipping and cutting out the design. When the fabrication process is complete, they end up with what looks like a dull block of glass. Most are about 6 inches square, but some are as large as 18 inches. When that block is sliced open, like a geode, colorful patterns and designs suddenly emerge.

"We really don’t know, until we cut it, what we have inside," Mortara said. "Our image is already in there, just waiting for us to open it up. That’s the enigma: How did it get there?"