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.
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.
Minerals such as amethysts are known for their color. For instance, Candler said citrine is yellow-colored quartz. Malachite is green, and azurite is blue, but both are copper. Morganite, a beryl, is also known as pink emerald. Green-colored beryls, or emeralds, are rarer than diamonds.
Most of the giant gemstones at the Perot exhibit were too large for personal adornment. And according to Candler, things like fluorite are also too soft.
“It wouldn’t take a lot of abuse,” he said, and hardness and durability are important factors when evaluating gemstones. The four C’s — color, clarity, carat and cut — also factor in.
Candler pointed out a piece of fluorite which was on loan from the Gail and Jim Spann collection.
“Jim and Gail Spann are internationally known collectors who loan or share their collection through the Perot and the Smithsonian,” he said. “These are [Dallasites]. They are [among] the most aggressive collectors of minerals in the world.”
Renowned collector Lyda Hill and Rob Lavinsky, a prominent dealer, are also local, Candler said.
One of the Tiffany necklaces on display captured the eye of Carrollton resident Stephanie Macdonald during her tour of the exhibit.
“I also love the rose quartz, the spherical one,” she said. “I like anything shiny and pretty.”
Candler said developing an eye for gemstones by looking at other examples is key to finding and amassing a collection.
He said some rocks might fracture a certain way, sparkle in a different way to catch your eye, or have a different shape than the rocks around it.
Whether it is faceted stones for jewelry, large crystals to display in a cabinet, pieces of petrified wood from grandma’s, or geodes at school, if someone is interested in any of those, Candler said they might be a rock hound.
“Rock hounding, like a lot of things in life, is whatever turns you on,” he said. “You don’t have to spend $10,000. You can spend 10 bucks and get a cool mineral.”
Candler said one of the problems that miners face is whether to sell a mineral as a specimen of uncut beauty to a collector or to a gem cutter.
“Some people really value those mineral specimens and will be aghast that you took one and cut it into a precious stone,” he said. “Other people couldn't care less about that crystal but want that precious stone. It may be worth money cut up into little bitty stones.”
Wearing a red agate belt buckle, Candler said another problem in keeping specimens intact is “you want to cut it so you can see what it looks like in the middle.”
Gems are faceted to allow the light to come in and reflect back to the eye, which adds value and beauty, he said. However, some are cloudy and unsuitable for cutting.
Geophysicist Dianne Brownlee said uncut diamonds are actually quite boring. As she talked, a wide-eyed boy wandered up inquiring whether the Hope diamond was among the collection of giant gems. It was not.
Brownlee, whose relatives had mined in Colorado, said she has collected her share of rocks, but it is more difficult to go underground these days.
“It’s harder to hunt now because everyone is very aware of the danger,” she said. “[Underground mines] can be chemically difficult as well. Now, I like to go mess around old dumps.”
Brownlee pointed out an ametrine “cutter crystal” among the giant gems, which was an exquisitely cut color merge of amethyst and citrine.
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Candler also mentioned the metaphysical properties of the rocks.
“Kunzite has special meaning for the metaphysical people,” he said. "I’m not one of those people. I do not discount their belief, I just don’t get excited in that way. They might be right."
Candler, who sometimes hunts for rocks in the Big Bend area, and in Colorado, said his favorite mineral is rhodochrosite.
“If you wanted to make this, you couldn’t,” he said gesturing widely toward the museum’s displays of gems and minerals.