CEDAR FALLS -- Henry Helene holds in his hand a 1798 American penny.

Worn but remarkably preserved, the coin features Lady Liberty, and on the reverse the words "one cent" are clearly discernible. It's about the size of today's quarter. Using a jeweler's loupe, Helene examines a 1542 Spanish reale, a coin bearing the hand-stamped names of Spain's King and Queen, "Carlos and Joanna."

"It's from the second issue of coins ever made in the Americas by Cortez," Helene marvels. "It was made in Zacatecas, Mexico, in Cortez's basement before his mint was finished."

The Spanish reale and American penny are among many coins, including Roman coins, and other archeological artifacts in Helene's collection.

Helene, a semi-professional treasure hunter, will be featured at the Black Hawk Gem and Mineral Show, April 1, at the Waterloo Center for the Arts.

"Treasure-hunter" is a romantic sounding term that conjures up all kinds of visions of discovering long-lost gold mines, digging for pirate booty, maybe even a diamond field, mingled with elements of danger and exhilaration. "One thing leads to another, and if you don't have the gumption to pursue it, you're in trouble. It's kind of like being a CSI, only you're following the facts and evidence from the earth," Helene explains.

His juices first began flowing in 1969, when he joined friends searching for the lost San Saba mines in Texas. In the 1980s, he began treasure hunting in earnest.

Helene has lived -- and hunted treasures and artifacts -- in Texas, California, Florida and Iowa. Engineering and science are areas of interest, but he's also raced top-fuel dragsters and worked as a machinist and fabricator. His forte is reading the signs of treasure.

"I'm a born researcher. I love that aspect of it, and it's natural for me. I can read old documents and read between the lines. I can study maps and details on other finds that have been made and use that information as a guide for making new finds. I've learned how to plot the path of a ship wrecking against the beach in a storm and how it is drawn back out by the waves to come crashing back again and again. When you can figure that out, you can extrapolate where booty might have been dropped each time it crashed," he explains.

His research also is aided by technology, including global positioning satellites.

In the 1980s, when his dad offered him a chance to purchase his home in Florida, Helene moved to Sebastian, Fla., and enjoyed beachcombing. If you picture a lone guy on the beach swinging a metal detector, you're only half right. Turns out he wasn't alone.

"I noticed this guy shadowing me on the dune. I called him down, and he asked me what I was looking for, how I knew where to look, and I described to him how the waves and beach settle old coins. Turns out the guy owned a diveboat company and I ended up becoming a consultant and working with them on treasure hunts."

As luck would have it, Helene also scored his biggest treasure to date on Sebastian Beach -- coins from the wreckage of a 1715 Spanish ship that sank in a storm near Sebastian. "A friend came to my house and urged that 'I had to see something.' So I went with him, and I'm looking at the beach and ocean and saying, 'What am I looking for?', when suddenly I saw a 10-foot anchor lodged in the sand. There'd been a hurricane out to sea, and the sea threw up thousands of silver and gold coins. It was Nov. 18, 1987 -- I won't forget the date."

Helene and his pals worked nonstop and subsisted on coffee for three days and nights, gathering the booty. "At low tide, we'd go out and pick up the coins. After the third day, word got out, and people swarmed the place," he recalls.

He also was consultant on a dive near Fort Pierce, one of the oldest communities on Florida's east coast, often called "the treasure coast." A cache of gold Spanish coins was found valued at more than $4 million. "One coin brought $50,000, because it was unique. Whenever you make a treasure find off Florida's coast, the first thing you do is contact the state archeology department and photograph and catalog the items. They send down an archeologist to authenticate the find. The state gets the first 25 percent of the treasure and the rest belongs to the company to divvy up."

Helene will be showing a DVD featuring the find at the Gem and Mineral Show.

Among his favorite treasures is an authenticated early painting by Remedios Varo, which he bought at a second-hand store for $4, now worth thousands; a heavy California jade pestle; raw silver nuggets; fragments of meteorites; countless arrowheads; a 150-year-old handmade miniature cross bearing the inscription "White Hawk; and a 1700s Kachina doll.

{M3Black Hawk Gem & Mineral Society Show

noon to 5 p.m. April 1

Waterloo Center for the Arts, 225 Commercial St.

Theme: "Nature's Magnificent Minerals"

Demonstrations of sphere-making, dealers, jewelry, a silent auction and free polished stones for children in attendance.

Admission is free, but donations are accepted.