Quick answer: Inclusions are minerals, fluids, or gas bubbles trapped inside another crystal. Common examples are rutile needles in rutilated
Inclusions: The Minerals Trapped Inside Other Minerals Read Post »
Quick answer: Agate, jasper, and carnelian are all chalcedony: quartz made of microscopic crystals. Agate is translucent and banded, jasper
Agate, Jasper, and Carnelian: One Mineral, Three Personalities Read Post »
Quick answer: Most citrine sold today is heat-treated amethyst: heating purple amethyst, mostly from Brazil, to roughly 400 to 500
Quick answer: Agatized coral is fossil coral whose original calcium carbonate skeleton was replaced by chalcedony, preserving the coral’s flower-like
Agatized Coral: How a Florida Reef Turned Into Stone Read Post »
Quick answer: Blue aragonite is calcium carbonate, the same chemistry as calcite but with a different crystal structure, tinted sky-blue
Blue Aragonite From Rio Tinto: A Sky-Blue Mineral From a Blood-Red River Read Post »
Quick answer: Bismuth’s stepped rainbow crystals are grown by melting refined bismuth metal and letting it cool. The edges of
Bismuth: Why This Metal Grows Rainbow Staircase Crystals Read Post »
Quick answer: Vivianite is a hydrated iron phosphate that starts nearly colorless or pale green and darkens to deep blue-green
Vivianite: The Crystal That Changes Color When You Look at It Read Post »
Quick answer: Flint is a hard, dense form of microcrystalline quartz (a type of chert) that forms as nodules in
Flint: The Stone That Built the Stone Age and Lit a Million Fires Read Post »
Quick answer: Pietersite is a brecciated tiger’s eye: fibrous quartz and amphibole that was shattered by geological forces and recemented,
Pietersite: Tiger’s Eye That Was Broken Apart and Put Back Together Read Post »
Quick answer: Smithsonite is zinc carbonate, named after James Smithson, whose bequest founded the Smithsonian Institution. The Laurion (Lavrion) mines
Smithsonite and Laurion: A Zinc Mineral From the Mines That Paid for Athens Read Post »
