Fiona Steele and Jack Begley Unearth French Gem Clue on Oak Island (Season 12, Episode 13)

In this installment of The Curse of Oak Island, the team’s search for historical truths and hidden riches takes a promising turn in two key locations: the swamp and Lot 5. Season 12, Episode 13, titled “Caissons Ho!”, highlights not only the physical excavation work but also the analytical minds of the team, including archaeologist Fiona Steele, veteran treasure hunter Jack Begley, and key experts like Laird Niven and Emma Culligan.

In the swamp, Rick Lagina, Alex Lagina, and Billy Gerhardt uncover well-preserved wooden boards approximately three feet below ground. The team suspects these may be remnants of early searcher activity—or perhaps something older, tied to the theorized network of tunnels and hidden caches that continue to elude confirmation. Rick notes the significance of finding wood at such a depth, suggesting persistent evidence that “people were working in the swamp for something.”

Meanwhile, on Lot 5, Fiona and her assistant Todd Langseth continue a long-term investigation of a mysterious round foundation. Jack joins them to examine a key test pit, where they soon recover two distinct objects: a small triangular hinge and a star-patterned piece of clear, cut glass. The discoveries, while modest in size, spark immediate excitement. Could they be part of a lost chest, or even a jewel?

Back in the Oak Island lab, archaeometallurgist Emma Culligan and archaeologist Laird Niven identify the “jewel” as high-lead-content flint glass, also known as paste—a simulated gemstone created in 18th-century France by jeweler Georg Friedrich Strass. This style of gem, once popular among French elites, marks a significant historical link. Even more compelling is the soil analysis: materials from the Lot 5 foundation closely match samples taken over 100 feet deep in the Money Pit area.

Marty Lagina and the team consider the implications. The artifact fits within the timeframe of the duc d’Anville’s 1746 expedition, raising the possibility that someone of wealth and influence was not only present on Lot 5—but potentially orchestrating larger operations tied to the island’s legendary treasure.

As Marty aptly concludes, the find is not just an isolated artifact but “one of the most significant things on Lot 5.” For Fiona and Jack, this episode represents a milestone—evidence that archaeology, science, and perseverance can shed light on a mystery centuries in the making.