Don't be alarmed by billowing smoke and crowds this Saturday in the parking lot of the Quinlan Visual Arts Center in Gainesville - it's simply a demonstration of fun with pottery.

Specifically, it's raku firing, which is an ancient Japanese technique of firing clay using smoke and intense heat to uniquely crack the glaze. Each piece is different, and spectators will have the chance to glaze their own Christmas ornament and watch it be fired, then take it home and know how it got its interesting design.

"We heat that (piece) up to about 1,900, 2,000 degrees. The piece will get red hot," said Mary Ann Klimek, who teaches pottery and stained glass classes at the Quinlan and helped organize the event. "You take it out of the kiln and throw it in combustibles - anything that will start on fire. And as the glaze cools it cracks, and that's where you get the traditional black cracks.

"It kind of looks like a windshield; it's pretty neat."

Olympic Kilns in Flowery Branch is providing its kilns for the day.

When raku pieces are finished, they are purely decorative - because of the firing process, the piece is vitreous, which means it will absorb water. And it is the final step in the process - putting the piece in a container of materials that will catch fire - that creates the unique black spiderwebs across the glaze.

"It's going to be a really neat day," said Amanda Kroll, assistant director at the Quinlan. "You can just come by and buy a pre-made ornament."

While Klimek said you can use different types of clay in the raku process, on Saturday they will be using a special raku clay, which can stand up to the high heat. Otherwise, she said, the pieces might explode - which is a real spectacle at night.

Raku clay "has special chemicals and a frit in it to help it withstand the thermal shock; they can explode," Klimek said. "That's what makes it spectacular ... If something explodes in the kiln it comes shooting out the top like fireworks, so I can understand the people at Olympic Kilns wanting us to use raku clay."