Quick, can you answer this question: A lovely type of the gemstone garnet is mined by ants: True or False?

If you’ve read all of the Kimberley West Gemstone Mysteries, you know the answer is true.

Yes, I’m talking about ants, those pesky little things that can ruin picnics. Anthill garnets — sometimes written as ant hill garnets — are a particularly beautiful variety of garnets found in Arizona. The gems are so lovely, in fact, that they’re often mistaken for rubies.

But don’t take my word it. Read what Kim’s grandfather has to say in The Pirate’s Ruby.

Kim has been poking around in the jewelry store’s safe, looking for red gemstones to use in a jewelry display. She opens a package (excerpt from the book is in boldface):

Six brilliant-cut rubies winked up at her. The deep red color perfectly matched the ruby pendant she sought to accessorize. But these stones were small, maybe a quarter carat each.

“Grandpa, what’s with the teeny rubies?”

He peered over her shoulder and grinned. “Not rubies.”

“But the color…” Kim frowned and reached for a loupe. She lifted one of the red gems and studied it under ten times magnification. The stone was flawless.

Rubies were never, ever flawless.

At least, that’s what Grandpa told her when teaching her how to identify gemstones. Even the most valuable rubies, he’d said, contain stray crystals, feather-like spots or needle-like lines.

Kim, of course, had demanded to know why.

Grandpa told her it must have happened when rubies were formed. Problem was no one knew exactly how rubies were created.

The current theory pointed to plate tectonics, the ancient collisions of continents that formed mountains. The intense pressure and heat melted stone and refined the minerals, grouping similar atoms together. When the rocks cooled, the new minerals condensed. Among these was corundum, a rare mix of aluminum and oxygen.

Corundum in its pure form was colorless. Mix in a bit of titanium and iron, however, and corundum turned the rich blue shade of sapphire. Corundum plus a small amount of chromium created ruby’s intense red.

Ruby’s chemical makeup explained its rarity, but not its inclusions. Many other gems, including diamond, could form without flaws. During her undergraduate days, Kim spent many lunch hours proposing and debating possible reasons with other geology students.

The same ruby trait that drove Kim nuts, however, helped Grandpa and other jewelers differentiate between rubies and imitations. If a natural red gemstone lacked inclusions, it was one of the ruby look-alikes — zircon, spinel or garnet.

The stone in her hand didn’t sparkle enough to be zircon. Of the remaining two possibilities, she decided to guess the more expensive.


Grandpa grinned. “Nice try. But, no, these are garnets. Anthill garnets.”

Kim frowned. Most of the garnets Grandpa stocked were pyrope garnets, the purple-red color most people associated with the gem. But he sometimes sold tsavorite garnets; she loved their emerald green color. And once she’d begged him to purchase a spessartite garnet so she could drool over the bright orange color.

But she’d never heard of anthill garnets.

The glint in his eyes told her he was itching to tell a story.

Folding her arms, she leaned against the counter and grinned. “Okay, out with it. What are anthill garnets?”

“They’re among the rarest gemstones,” he said. “Found only in the Navajo Nation in Arizona.”

Knowing she was falling into a trap, she played along. “Garnets aren’t rare.”

Grandpa flashed his “gotcha” smile. “Ah, but garnets mined by ants are exceedingly rare.”

She blinked. From the gemstone’s name, she’d expected his story would have something to do with anthills. But she was thinking more along the lines of “certain kinds of anthills indicate the presence of garnets” not “those nasty critters that ruin picnics don safety helmets and go mining.”

“You wanna elaborate on that?”

Grandpa leaned against the counter, unconsciously mimicking her body language.

“When they’re excavating their tunnels, the ants carry small garnets to the surface,” he said. “No one knows who, exactly, first discovered the garnets mixed into the ants’ hills, but I like to think it was a Navajo princess. Because of the blood-like color, legend claims the Navajos used the garnets as bullets.” He shrugged. “I don’t believe that; the Navajos were peaceful, so why would they spend time worrying about bullets?”

“Anyway,” he continued, “today’s Navajos collect the garnets from the anthills and sell them to gemologists. And that’s why we have anthill garnets.”

“Back up a second. Why do the ants bother carrying garnets to the surface?”

He chuckled. “This is why I never told you the story when you were a child. I knew you’d ask why.”


He shrugged. “I can’t answer the question. No one knows why. Some people think that because garnets are heavier than sand, the ants use the garnets to strengthen their hills. Other people say the garnets are in the way, so the ants are just moving them. There are even people who claim the ants don’t mine the garnets at all, that the garnets are appearing because of natural erosion.”

Kim snorted. “If the worker ants were female instead of male, people would claim the ants like to see the garnets glinting in the sun.”

She lifted one of the garnets and held it to the light. “It’s amazing how much they look like rubies.  .  . Oh. My. Gosh. Grandpa!” She gripped his arm. “I just had a wonderful idea!”

“No, you cannot salt an ant farm with garnets.”

“But isn’t that the only scientific way to figure out why the ants remove the garnets? . . .”

Hmmm . . . I wonder if anyone ever has dumped a few garnets into an ant farm and watched to see if the ants immediately put on their mining hats and hauled the gems upward . . .

When I was doing research for The Pirate’s Ruby, I actually found a YouTube video about anthill garnets. You can view it by clicking below.