Something else caught his eye, though.
In the dirt along a levee, about 10 miles deep into the wetlands, Rubinstein found a gold pendant, with sapphires forming a cross inside a circle of diamonds. One edge of the penny-sized medallion was melted and misshapen.
It may have fallen from the sky. Rubinstein was hunting near the crash sites of two airplanes that went down in the same area: Eastern Flight 401, a New York flight that crashed as it prepared to land in Miami in 1972, and ValuJet Flight 592, a 1996 flight to Atlanta that caught fire shortly after takeoff and plummeted into the remote swamps west of Miami.
Rubinstein hopes to return the jewelry to its rightful owner.
"We've got to get this back to the family, if we can," he said last week.
All 104 passengers and five crew members aboard the ValuJet flight died. The Eastern flight carried 163 passengers and 13 crew members. Seventy-seven people survived, thanks in part to a Homestead man who was catching frogs from his airboat that night. He pulled survivors onto his airboat and turned his headlamp skyward so rescue helicopters could find the crash.
Invasive pythons have been able to disappear into the Everglades for a reason. Sawgrass gets its name from its sharp edges and can grow tall enough to hide predators and any sign of civilization. The wetlands are best traversed by an airboat, and guides warn tourists that anything dropped into the murk is gone for good.
Eastern Flight 401 passenger Ron Infantino spent five hours pinned by debris in the water and sawgrass, holding onto the armrest of what had been his seat on the airplane. The crash stripped him of everything, leaving him naked except for the elastic of his socks. He screamed for his wife of 20 days, Lilly, but he never heard her voice again.
"I've always wondered: Could you imagine if I went back out there and found my wallet? But, no," he said. "It took them two days to find Lilly."
His first thought of his wife when he saw a picture of the pendant Rubinstein found, but he didn't recognize it as a piece that belonged to her. Infantino, who is raising money to build a memorial to the people lost on his flight, praised Rubinstein for reaching out to the survivors and the victims' families.
When Rubinstein got the pendant home in February, he dropped it into a jewelry cleaning solution, expecting it to disintegrate. Instead, it became more lustrous and revealed an intricate leaf pattern.
The Coral Springs man, who works at a construction firm, got in touch with the Florida Gold Coast Gem & Mineral Society, which posted his find in an online forum for jewelers. Stephen Walker of Walker Metalsmiths in Andover, N.Y., spotted the post and offered his expertise in Celtic jewelry to Rubinstein.
Walker suspects the pendant belonged to someone aboard the ValuJet flight because Celtic jewelry was scarce in the 1970s and didn't become popular until the 1990s.
The pendant's bright gold color, even where it melted, indicates that it was made from high-carat gold, he said.
"Diamonds will survive anything, and sapphires will, too. These were the ideal materials to survive this. A 14-carat gold would turn into a glob," he said.
Rubinstein also took the pendant to Robert Moorman, owner of Carroll's Jewelers in Fort Lauderdale. Moorman recognized the religious symbolism in the piece, and he determined that it was handmade from 18- or 22-carat gold, probably in the 1800s or late 1700s.
Rubinstein and Moorman have a few strong leads about the pendant's possible owner.
"A perfect situation would be someone saying, 'Here's a picture of so-and-so and they're wearing it,' but you don't always get perfect," Rubinstein said.
If he never finds the rightful owner, Rubinstein plans to give the pendant to a museum or the Archdiocese of Miami.
"It didn't belong out there. It doesn't necessarily belong to me," Rubinstein said.