Geodes, Nodules, and Vugs: What the Terms Actually Mean
Quick answer: A geode is a hollow, roughly round rock with a crystal-lined cavity inside; a nodule is a similar
Geodes, Nodules, and Vugs: What the Terms Actually Mean Read Post »
Trace Elements: The Impurities That Actually Give Crystals Their Color
Quick answer: Most crystal colors come from trace elements present at parts-per-million levels. Chromium makes ruby red and emerald green;
Trace Elements: The Impurities That Actually Give Crystals Their Color Read Post »
Birthstones, Decoded: What Your Birth Month Gem Actually Is Geologically
Quick answer: The modern birthstones are: January garnet, February amethyst, March aquamarine, April diamond, May emerald, June pearl, moonstone, or
Birthstones, Decoded: What Your Birth Month Gem Actually Is Geologically Read Post »
Pseudomorphs: When One Mineral Wears Another Mineral’s Shape
Quick answer: A pseudomorph is a mineral that has taken the exact outer shape of a different mineral it replaced,
Pseudomorphs: When One Mineral Wears Another Mineral’s Shape Read Post »
The Mohs Scale: A 200-Year-Old Ranking That Still Runs the Rock Shop
Quick answer: The Mohs scale ranks minerals from 1 to 10 by scratch resistance: talc 1, gypsum 2, calcite 3,
The Mohs Scale: A 200-Year-Old Ranking That Still Runs the Rock Shop Read Post »
Fluorescence: Why Some Rocks Glow Under UV Light
Quick answer: Fluorescence is when a mineral absorbs invisible ultraviolet light and instantly gives it back as visible color, stopping
Fluorescence: Why Some Rocks Glow Under UV Light Read Post »
Basalt’s Hidden Cavities: How a Lava Flow Grows Crystals
Quick answer: Basalt lava flows contain gas bubbles (vesicles) that froze in place as the lava cooled. Over thousands to
Basalt’s Hidden Cavities: How a Lava Flow Grows Crystals Read Post »
Reading a Specimen Without a Label: What Rockhounds Actually Look For
Quick answer: Without a label, rockhounds identify a specimen through a short series of tests: hardness (the scratch test), streak
Reading a Specimen Without a Label: What Rockhounds Actually Look For Read Post »
Paterson, New Jersey: The Trap-Rock Quarries That Put American Minerals on the Map
Quick answer: The trap-rock quarries of Paterson, New Jersey, cut into the 200-million-year-old Watchung basalt flows, produced some of America’s
Paterson, New Jersey: The Trap-Rock Quarries That Put American Minerals on the Map Read Post »
Travertine at Ilion Gorge: The Same Rock Behind the Colosseum, Growing in Upstate New York
Quick answer: Travertine is a banded form of calcite deposited by springs as carbonate-rich water releases carbon dioxide, and it