Look out for some interesting stones at Crater of Diamonds

With more than 40 different rocks and minerals at the Crater of Diamonds State Park, visitors make interesting discoveries every day.

“While most are fairly easy to identify, a few require closer examination,” said Waymon Cox, park interpreter. “One unusual stone that our visitors occasionally find is called a pseudomorph, and the name itself offers a clue as to why this type of mineral can be hard to recognize.”

The word pseudomorph literally means, ‘false form,’ Cox said.

“These strange specimens develop when one mineral replaces another but maintains the shape of the original. The resulting stone has the appearance of one mineral but the density, hardness, and other characteristics of another,” he said.

The most common pseudomorph found at Crater of Diamonds is called a silicate, after calcite pseudomorph. Silicate is a component of many minerals, including quartz and jasper. Calcite from the park is a soft mineral, with a cloudy white color and a flat and boxy shape.

“A silicate after calcite pseudomorph usually looks like a cluster of calcite crystals that has melted together. Unlike our native calcite, however, it can be several different colors, depending on other elements that were in the silicate when it dissolved and replaced the calcite underground,” he said.

Although diamonds are the chief attraction at Crater of Diamonds, other colorful rocks and minerals can make a day at the park more exciting. Watch for pseudomorphs during your next visit to the Crater of Diamonds, Cox said.