Denver Gem & Mineral Guild


A curated collection of videos and news stories from around the web, of interest to the local rockhound community.

Amazonite and Smoky Quartz - Photo by Ron Wolf
Photo by Ron Wolf

A Visitor’s Guide to Colorado Gemstones – Colorado has a lot to offer gemologists and rock hunters. Before you visit, learn about Colorado gemstones as well as notable gem shows, museums, and clubs. – by Addison Rice, IGS

The discovery, mill and tunnel that shaped Colorado’s gold destinyThe story of the Argo Gold Mill and Tunnel (includes reference to Beth Simmons (DGMG newsletter editor and past president) and her book. By Seth Boster,  

Hiking trail featuring ‘134 fossilized dinosaur footprints’ now public land in Colorado By Spencer McKee, OutThere Colorado, April 10,2024 – Coloradans now have another dinosaur track site to visit. Plus, it’s located in one of the most scenic parts of the state. . .


35 Most Valuable Gemstones, From Least to Most Expensive – A number of the most valuable gemstones are new discoveries that have only been found in recent decades.  – Story by Liz Sinclair and Craig Donofrio, Work+Money, February 15, 2024.

(NOTE – many older Guild members have collected at the WORLD’S BEST mine for #13 on the list)

historic Sers Geiger Counter Ad

THAT TIME THE U.S. GOVERNMENT ASKED ROCKHOUNDS TO HUNT FOR RADIOACTIVE MATERIAL – In the annals of American history, few episodes are as incredible as the mid-twentieth-century uranium boom . . . – Story By Don Gerig, Rock Seeker, February 13, 2024

Top Spots for Gem hunting in the US – When you think of mining for the “big four” gemstones — diamondrubysapphire, and emerald — it’s easy to imagine places like India, South Africa, and Colombia. However, you can find these stones and many others at plenty of gem hunting spots in the United States. – by Donald Clark, International Gem Society.

Fairy Cave

America’s Top Gem Sites – slideshow from

Colorado dinosaur lab builds prehistoric displays for museums around the world – Some projects at the Rocky Mountain Dinosaur Resource Center in Woodland Park take up to three years to complete for a full dinosaur skeleton reconstruction. – Story by Leslie James, Out There Colorado (2/1/2021)

How to Tell if Amber is Real or Fake: A Guide to Testing Authenticity –  The amber market is flooded with fakes trying to cash in. Story by Jeremy Hall, Rock Seeker (9/1/2023)

Blue Topaz
Silver ring with blue topaz. Jewelry and photo by Mauro Cateb, CC 2.0

Gemstone Care Guide – Learn how to best maintain your gemstone jewelry and what kinds of stresses and cleaning methods to avoid. Story by Dr Gerald Wykoff, International Gem Society.

Concretions: What Are These Bizarre Rock Formations? (And What’s Inside Them?) – Concretions are a bit of an oddity in the world of rocks and minerals.  Story by Jeremy Hall, Rock Seeker.

Slate Creek, Eagles Nest Wilderness by John Fielder

John Fielder’s Lifetime of Colorado Photography Can Now be Viewed Online – 

Anyone at home can now view the vast and varied beauty of Colorado through the eyes of the state’s most celebrated landscape photographer – over 6,500 images – at History Story by Seth Boster, OutThereColorado (6/6/2023).

Colorado Map
Colorado map from Library of Congress

Colorado is a Hexahectaenneacontakaiheptagon! – Colorado looks like a rectangle. It isn’t. The Centennial State has not four, but 697 sides. Story by Frank Jacobs, Big Think, (January 2023).

Pixabay photo

The Story of Silver in the United States – Humans have held silver dear since antiquity. In the ancient world, silver held a cultural and religious value that rivaled gold and precious jewels . . .
This story from was recommended to us by Penny from Mr. Wood’s Geology Study Program.

Into the Dinosaur Valley – Prehistoric Wild America Dan Snow travels across America retracing the very first discoveries made by fossil hunters nearly 200 years ago, from Wyoming to the foothills of the Rocky Mountains. He reveals how the very first discoveries of the most amazing dinosaurs of all time were made, including the T-Rex and Diplodocus, and learns why America’s stunning wild West is such a hotspot for dinosaur remains.

Jim MeKeeman says – “Our little intrepid band of WIPS fossil hunters were part of this documentary done on the Bone Wars.  John Foster has some great film time here as well. They came up to Nail Quarry on August 21 to film us in action.” (12/11/2022)

Fossil Cycad 1935
NPS Photo

The National Park That Was Stolen to Death – Fossil Cycad National Monument in South Dakota held America’s richest deposit of petrified cycadeoid plants . . . until it didn’t. Story by Cara Giaimo, Atlas Obscura (7/11/2017)

Amber Mines in Mexico Offer Hope, Hazards, and ‘A Perfect Time Capsule’ – In a network of dark tunnels, workers risk their lives to find coveted treasures that preserve a distant past. – APRIL 28, 2021

Real vs. Lab Diamonds | What’s the Catch – This short, fast-paced video discusses the history of diamond mining and asks, “if lab grown diamonds are indistinguishable from mined diamonds, why would we pay more for a mined diamond”? – by The Hustle, 2/12/2024

New Utah Rockhoundr Interactive Map Available – The Utah Geological Survey, in partnership with the Bureau of Land Management, has launched a new rockhounding application highlighting where to find rocks, minerals and fossils in Utah. – Utah Geological Survey, August 3, 2022

Radioactive Diamond Battery

The Radioactive Diamond Battery That Will Run For 28,000 Years – Imagine a battery that provides green energy, saves taxpayers thousands of dollars, and never runs out of power. – Julie Hambleton The Premier Daily, December 15, 2023 

Walt Disney’s unusual Colorado connection – What’s the oldest attraction at Disneyland? It’s a 5-ton petrified tree stump from Colorado that’s between 50-70 million years old. – By Terry Torrones; The Gazette, Jan 20, 2020

How to spot a Fake Diamond – 13 at-home tests to spot a fake diamond. Story by Addisone Rice, IGS

Emeline Rooney
Emeline Rooney outside the family homestead. Photo courtesy Randy Rooney.

The Legend of Rooney Ranch, a Colorado Landmark Refusing to Fade Seven Generations Later – Adjacent to Dinosaur Ridge, is Colorado’s oldest ranch still being carried on by its founding family. Story by Seth Boster, The Denver Gazette (5/7/23).

A Guide to Gem Cutting Styles – Gem cutting styles refer to the shape and arrangement of facets. Story by Donald Clark and Phoebe Shang, International Gem Society.

Down to Earth and Out of This World: A Look at Colorado’s Old Rock Shops – Colorado’s oldest rock shops date to the 1970s, a time that stirs nostalgia and visions of an open road and a changing America. Story by Seth  Boster, The Denver Gazette (6/18/2023).

photo from

The Mystery of North America’s Missing Eastern Dinosaurs – the Eastern US has plenty of rocks of the right age to find dinosaurs. So why have so few been found? Story by Zaria Gorvett, BBC (2/2/2023).

AI meteorite image
image by synthesis AI studio

A 15-metric ton meteorite crashed in Africa. Now 2 new minerals have been found in it – Story by Kristen Rogers, CNN, Sunday (12/25/2022).

Image by Enrique from Pixabay

Treasure Worth Millions May Still be Hidden in ‘Lost’ Colorado Cave – story by Tamera Twitty, Out There Colorado. (11/7/2022).

Image from "A Brief History of Colorado Through Time"

Colorado Once a Coastal Environment, Mapping from CU Boulder Shows – Oceanfront property in Colorado? See the fabulous video by the University of Colorado Boulder’s Interactive Geology Project to get an amazing overview of Colorado geology. Story by Spencer McKee, OutThere Colorado (2/28/2022)

Comet photo

A Comet Impact May Have Paved the Way for Human Civilization – The Younger Dryas impact hypothesis argues that a comet strike caused major changes to climate and human cultures on Earth about 13,000 years ago. Story by Stephen Johnson, Big Think (6/29/2021).

Jeff Self and Donna Ware
Jeff Self & Donna Ware

Getting the Dirt on Colorado’s Precious Stones, listen to the interview by Ryan Warner with DGMG members Jeff Self and Donna Ware for Colorado Public Radio (1/2/2014).

The story of Charlotte Hill, a Colorado homesteader who collected ‘staggering’ amount of fossil specimens – Numerous fossils collected by Charlotte Hill in Florissant are preserved in the Smithsonian’s Museum of Natural History, and at Harvard and Yale universities. By KELLY HAYES

10 ‘can’t miss’ mine tours that show off the ‘Wild West’ era of Colorado – Take a dive into Colorado’s rich mining history with these mine tours. by Piper Russell, OutThere Colorado, April 30, 2024.


A Web Site That Lets You Find Your Home Address on Pangea – Software engineer Ian Webster has created a website that lets you see how the land masses on planet Earth have changed over the course of 750 million years. – from Open Culture, 2/19/2024

Wheeler Geologic Area

Wheeler Geologic Area, Creede, Colorado – This once-popular otherworldly landscape was formed by one of the largest volcanic eruptions in history. – Atlas Obscura

Castle Rock

9 Different Types of Agate (with pictures) – Agate is a strange word, used in a wide variety of ways . . . – by Jeremy Hall, Rock Seeker, June 18, 2022

Why dinosaur footprints inspired paleontologist Martin LockleyThe late scientist is credited with creating a subfield devoted to the trace fossils left behind by the extinct reptiles. – | Popular Science

How Miners Find and Excavate the most Expensive Amethysts in the World – See this amazing video! –  by Abby Tang and Clancy Morgan, Business Insider, Nov. 20, 2023

A Timeline of Colorado’s Mining Past – Story by Seth Boster, Out There Colorado (6/19/2022)

Your Exploration Guide for Crystal Digging at Salt Plains National Wildlife Refuge – Young and old alike love finding treasure buried in the sand, and for a minimal car entry fee, you can spend the afternoon looking for selenite crystals. Story by Little Family Adventure (5/17/2023)

Atlas Obscura

10 Places to Experience Nevada’s Extraordinary Geological Gems – We’re talking massive deposits of gemstones and minerals, such as jasper, agate, onyx, and silver, not to mention more mined gold than anywhere else in America.

Pyromorphite photo provided by Weinrich Minerals

48 Outstanding Idaho Rockhounding Sites for 2023 – Idaho is a scenic state that offers a treasure trove of rocks and minerals, presenting a geological playground for collectors and adventurers. Story by Dr. Keith Jackson, (6/13/2023).

Mt Antero
Sandra Gonzales and her 83-year-old mother, Viola Padilla on Mt. Antero (Parker Seibold, The Gazette)

A Never-Ending Education: A Colorado Rockhound’s Journey to ‘Nature’s Art” – Gonzales puts on the Denver Mineral, Fossil, Gem and Jewelry Show, a week-long extravaganza starting Sept. 8 at . . . Story by Seth Boster, The Denver Gazette (6/1/2023)

Fossil Daddy

Paleontology enters pop culture on Tik Tok with Fossil Daddy – On his TikTok account, he makes fossils fun for adults by describing them in ways that people can understand. Story by Jane Herz, New York Post (3/16/2023).

Rarest Mineral on Earth
The sole specimen of kyawthuite. Image Credit: Natural History Museum of Los Angeles County

There is Only One Specimen of the Rarest Mineral On Earth – Among the Earth’s 6,000 identified minerals, only one is known from just a single sample. Story by Stephen Luntz, IFLScience (1/26/2023).

image by Synthesys AI Studio

North America’s evidence of Asteroid Strike, Dinosaur Mass Extinction First Discovered in Colorado – story by Leslie James, Out There Colorado. (8/17/2021)  This article includes directions on how to find the K-Pg boundary on South Table Mountain in Golden.

Hear about recent discoveries at the Great Sand Dunes National Park! – Video by History Colorado. To learn more, check out Marilyn Martorano’s extended talk, presented to the 8th Repository Confab of the Colorado State-Approved Museums and Repositories (2/8/2021).

Page last updated 5/27/2024

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