Originally Posted: October 11, 2016
It all started with a load of gravel hauled in from around the Trinity River.
When Bill Candler, former president of the Oak Cliff Gem and Mineral Society, was 5 years old he found a few fossils out in the driveway and displayed them in his bedroom. He was incensed when he later discovered them in the driveway once again after his mother had thrown them out. He was a rock hound.
This weekend, Candler toured the Perot Museum of Science and Nature’s Giant Gems of the Smithsonian collection, which has never been seen together anywhere. Resting among the colored brilliance, sits a golden topaz weighing more than 10 pounds.
“We find topaz here in Texas,” Candler said. “The rare ones have a little blue tint.”
Blue topaz, the state gemstone of Texas, can be found in the central part of the state around Llano, Candler said. The mineral comes in many colors, and the clear ones can be irradiated, which turns it a blue color and makes the gem more likely to be hoarded by a collector.
“While most of the world’s blue topaz has been enhanced by irradiation, Texas’ is naturally occurring and is sometimes faceted or cut to show a star in the middle of the stone,” he said.
While the terrain in North Texas holds fossilized treasures, because limestone is the predominant rock, collectors can’t expect to find many coveted specimens lying around locally, Candler said. They may have to wander over to East Texas where petrified wood can be found, or to the Big Bend area which has some of the finest agates in the world.
Gem and mineral enthusiasts also score finds during field trips conducted on private ranches. Different parts of the country produce different types of specimens, Candler said, pointing to a display of tree-like, dendritic gold in one of the museum’s regular exhibits and noting that many examples come out of California. He also said some of the finest specimens were hauled out of mines inside a miner’s lunchbox.
Candler said while rock picks are essential, a rock hunter’s most important tool is a dollar squirt bottle with water in it to help get the dirt off so a person can tell whether or not they want to carry a rock back to their car. All rock hounds collect “leaverite,” Candler said, which he described as “a rock you want to leave right there.”
“You don’t want to carry 500 pounds of rocks back to your car,” he said.
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A green beryl, or emerald, necklace.
courtesy Perot Museum
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Minerals form inside a hollow spot of a molten rock, Candler explained, and when fluid cools off fast crystals grow. But the slower it cools, the bigger the crystals. Slow cooling air pockets within the earth give minerals a chance to find each other, he said, so you might have a pocket of fluorite, quartz, aquamarine and topaz all together.
“Usually you’ve got a bunch of elements combined to make one mineral,” said Candler, who studied geology prior to business and real estate at SMU. READ MORE