Tabla de contenidos para October 2025 en Rock and Gem

Boo! It’s that time of year again! Spooky season has arrived, and our team is having way too much fun with all the spooky rock stories. It’s funny, when I initially suggested an informal spooky-themed issue, everyone kind of scoffed at it. Since then, spooky-themed stories are in every writer’s pitches for planning. On a personal level, Stuart and I had a ton of fun picking out minerals for our Field Guide column. Transylvania is a mineral powerhouse, and it was hard to narrow things down. The reason people initially scoffed at spooky rocks is that they didn’t see the connection. But when you look, you often find. Beyond the textbook, rocks are everywhere and in everything, especially in our pop culture and holidays, where it may not be so…

Howlite was first discovered in Nova Scotia in 1868 by Henry How. He originally named the stone silicoboro-calcite, which was eventually renamed howlite in his honor. Since then, the main source of this mineral has been found in great abundance in the Tick Canyon in Los Angeles County, northwest of Pasadena. HISTORY BEHIND HOWLITE – AN UNINTENTIONAL DISCOVERY Through the uncovering of borate deposits came about the development of the Sterling Borax Mine. Borates have many unique properties that make them an economically useful mineral, resulting in over a decade-long mining effort. Through these efforts came a byproduct of their mining, howlite. The howlite was considered waste and tossed aside since the mine’s primary focus was on borate minerals. Since then, rockhounds and collectors have collected this waste product, appreciating…

The Best Archaeopteryx Yet Archaeopteryx has been an icon in the world of paleontology ever since the first one was uncovered in 1861. Called the “Urvogel” by the Germans who discovered it in Solnhofen, Bavaria, this Jurassic fossil was instantly considered the missing link between non-avian dinosaurs and avian dinosaurs, AKA birds. Remarkably, given its fame, only 13 specimens have been described in all the years since. Well, there’s a new Urvogel in town. They call it the “Chicago Archaeopteryx” (because that’s where it’s housed), and it’s the best one yet! In the journal Nature, a joint Chinese-American team led by Jingmai O’Connor (Field Museum of Natural History, Chicago) and Han Hu (Chinese Academy of Sciences) gives a detailed description of an exquisitely preserved specimen that’s essentially complete, with bones…

Maribel Caves, Hotel and Spa in Manitowoc County, Wisconsin, holds tales of a haunted past with rumors of fires, witches, murders, gangsters and underground passageways that were actually the nearby caves. Today, the hotel lies in ruins on private property, but right next door, in Cherney Maribel Caves County Park, an extensive cave system is undergoing excavation by the Wisconsin Speleological Society (WSS). New Hope Cave, open to the public for walking tours, and at least 10 other caves are nestled in the cliffs of the park’s hiking trails, some available for private tours to serious spelunkers. Along the West Twin River, the Maribel cave system was discovered in 1892 on the property of Henry A. Alrich. The land was later purchased by Charles Steinbrecher, whose brother, Father Francis X.…

Whether you’re in it for science, beauty, spooky stories, or all of it, Transylvania’s minerals offer a little something for every rockhound. Deep in the heart of Romania, the Carpathian Mountains are known for gothic lore and vampire legends. In this land of Dracula, Transylvania’s rugged geology, shaped by volcanic activity, has made it one of Europe’s most mineral-rich areas. Transylvania History Transylvania’s mineral wealth drew the fascination of several distinguished aristocrats who helped shape early mineral science. Ignaz von Born (1742–1791), born in Alba Iulia, became one of Europe’s foremost Enlightenment mineralogists, lending his name to the mineral bornite. Franz-Joseph Müller von Reichenstein (c.1740–1825), a high-ranking mining official, discovered the element tellurium in 1782 while studying local ores, and later had the tellurium mineral müllerite named in his honor.…

If elements were rated by their popular image, sulfur wouldn’t have a chance. Just the mention of the word conjures unsettling thoughts of noxious volcanic gases, acrid smoke, odors of decaying organic matter and even the fundamentalist Christian “fire-and-brimstone” concept of Hell. But, image problems aside, sulfur has a lot going for it. Widely collected for its beautiful, bright-yellow crystals, sulfur has been a staple in medicine for 4,000 years and, under its old name “brimstone,” appears frequently in both the Bible and alchemical texts. Today, sulfur is a major industrial commodity with myriad uses. And, in a contradiction of a fundamental tenet of mineral-resource supply and demand, sulfur use has reached record highs, yet sulfur mining has virtually ceased. FUMIGANTS AND GUNPOWDER The Chinese were using sulfur medicinally by…

Not all treasures stay buried; some endure. More than 71 million years ago, beneath the waves of a vast inland sea, spiral-shelled ammonites thrived along what is now southern Alberta, Canada. Over time, their shells—layered in delicate aragonite—were preserved and transformed, capturing the full spectrum of light. Today, this transformation is known as Ammolite: a rare and radiant gemstone, alive with shifting color, carrying the legacy of the ancient sea in every iridescent layer. “In the fossil-rich beds of southern Alberta, something uncanny glimmers beneath the surface. Ammolite refuses to fade. Polished and preserved, these ancient remains shimmer in electric greens, fiery reds, deep blues and ultraviolet purples—as if channeling a ghostly memory from a lost world.” In the fossil-rich beds of southern Alberta, something uncanny glimmers beneath the surface.…

Along with black cats, witches and jack-o’-lanterns, cemeteries are iconic symbols of Halloween—and for good reason. Shrouded in mystery, superstition and folklore, they can elicit feelings of foreboding and fear. For most people, cemeteries—the word stems from the Greek koimētērion meaning “sleeping space”—are places of quiet and solitude for contemplation and the commemoration of the dead. But as repositories of history, culture and art, cemeteries also draw historians searching for clues to the past, antiquarians studying gravestone styles and genealogists tracing ancestral roots. Geologists and rockhounds are also attracted to cemeteries, but for different reasons. With their rows of silent headstones, cemeteries are open geology textbooks that are literally written in stone. And they provide a great opportunity to study sedimentary, metamorphic and igneous rocks that have been cut and…