Calcite Fossilized Clams Collecting in Florida

Calcite Fossilized Clams Collecting in Florida
Calcite Fossilized Clams Collecting in Florida. This is a large Fossil Clam shell on matrix from Florida. Photo: Bryan Major 

Calcite Fossilized Clams Collecting in The Fort Drum Mine, also known as the Rucks Pit or Fort Drum Crystal Mine

Calcite crystals represent the most commonly-collected mineral from Florida. As most of Florida is underlain by Tertiary to recent marine limestones, the potential for crystal finds exists just about anywhere these limestones are exposed – most prominently in active limerock quarries. 

The Fort Drum Mine, also known as the Rucks Pit or Fort Drum Crystal Mine, was first recognized as a geologically and scientifically important locality as far back as the early 1990's. During that time, Dr. Thomas M. Scott, Assistant Florida State Geologist, discovered the presence of calcite spar geodes within a gray sandy limestone in the old Rucks pit (now the large recreational lake adjacent to the mine campground).

Besides the presence of the calcite geodes, the mine was of special interest to scientists in that it was continuously pumped, allowing for in situ collecting of fossil specimens and for direct study of the exposed geological formations. The calcite geodes were also of special interest, as they had formed as large aggregations of dogtooth spar growing inside fossilized clams (bivalve mollusks) and whelks (gastropod mollusks). As far as is known, this type of dogtooth spar geode is unique to the Fort Drum Mine.

Calcite Fossilized Clams Collecting in Florida
Ruck's Pit Calcite Clam. Photo: Rockhounding Florida

The gem-like crystals were discovered after the hard limestone deposits came to be excavated for aggregate.

In 2008 the quarry known as Ruck's Pit was closed and allowed to flood.

Nowadays another location 2 blocks west have been opened. Ruck's Pit in Fort Drum, Florida, which is owned and operated by Eddie Rucks, is the PRIME locality to find minerals and fossils combined in the same specimen. Specimens from this locality range from 1.6 to 2 million years old.

What you’ll find:

  • Loose, gem-quality calcite crystals and crystal clusters. Some individual crystals can be over an inch long.
  • Large, fossilized clams filled with calcite crystal
  • Other fossilized shellfish, like whelks and olive shells. On rare occasions, you’ll find one of these filled with tiny crystals.

Tips for happy hunting:

  • Wear comfortable clothes that you won’t mind getting dirty. Because they will.
  • Boots – or other shoes with ankle support – are a good idea. Loose rocks can give you a twist.
  • Wear gloves. The tiny, fossilized shells that make up the rock can have rough edges.
  • Bring a hammer, chisel, hoe and flathead screwdriver. The driver is a valuable tool for carefully loosening the dirt and rock around your fragile finds.
  • Bring buckets. For adults, the mine charges $30 for a five-gallon bucket. For kids under 12, it’s $15.
  • Bring newspapers. Calcite is “soft” crystal and easily scratched. Wrap your finds before they go in your bucket.
  • Bring a cooler and plenty to drink.
  • Wear sunscreen. While there are shade pavilions, when you get the “crystal fever,” you’ll forget how long you’ve been standing in the sun.

Calcite Fossilized Clams Collecting in Florida
When you are digging in the right area, you will
find whole beds of clams like these two.
Photo: Mineral Movies
Ruck’s Pit is in the midst of a transformation and will eventually become a full-service campground. There’s already a swimming beach at the lake, so if you get too hot, you can take a dip. The lake is also stocked with bass, bluegill, catfish and tilapia for catch-and-release fishing.

It’s a pretty informal operation, and its owners are not always on-site. So it’s a good idea to call ahead and let them know you’ll be there. They’ll stop in to collect the mining fee. Bring cash. Exact change is best. It’s that informal.

The mine is typically open seven days, from 8 a.m. to 5 p.m.
Address: 28320 NE 55th Ave, Okeechobee, FL
Reach Edwin Ruck at 863-631-0691.

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