Named from Greek mimetes ('imitator') because it looks startlingly identical to green-yellow Pyromorphite, Lead Chloro-Arsenate Mimetite pulls off one of mineralogy's weirdest geometric stunts! When Phosphate and Arsenate battle inside Cumberland England veins, mismatch strain warps straight hexagonal needles into plump, curved pumpkin-colored barrels dubbed Campylite—while southern China's Pingtouling Mine grows dazzling egg-yolk botryoidal clusters! Swap Phosphate vs Arsenate ions, bulge barrel curvature, and test white-light vs 365 nm UV.
San Pedro Corralitos / Hat Yai Yellow Mimetite • Named 'Imitator' 1832
Formula: Pb5(AsO4)3Cl
Mechanism: Arsenate Replaces Phosphate In Heavy Lead Chloride Lattice
Mimetite (SG 7.24): Heavy lead chloro-arsenate forming blazing canary-to-apricot hexagonal prisms and plump botryoidal crusts!
Wait — Did You Know?German mineralogist Johann Breithaupt named Mimetite in 1832 after Greek 'mimetes' ('mimic') because yellow-green arsenate crystals disguised themselves so convincingly beside Pyromorphite that miners couldn't split them without a blowpipe garlic test!
Select Specimen or Control Sample (8 Profiles)
Click any Mimetite, Campylite, or Pyromorphite-series member to inspect As/P ratio, barrel warping, and toxicity care:
Mix mid-series Arsenate + Phosphate to swell flat hexagonal prisms into chubby Cumberland Campylite barrels!
Arsenate (AsO4 vs PO4)88%As
Mid-Series Barrel Bulge Strain76%
CrO4/Fe Chromophore Depth72%
Hexagonal P63/m Lead Apatite-Group & Strain-Warping Telemetry
Live Diagnostic Telemetry
Formula & As/P BalanceMohs 3.5-4.0 | SG 7.24 (!!)
Hardness / Specific GravityResinous-Adamantine Yellow-Orange
UV Glow & Imitation NoteWhite Powder Streak!
Blowpipe Clue (Historians): Old assayers heated a pinpoint grain on charcoal—arsenic released unmistakable garlic scent while pure Pyromorphite did not!
Why does this happen atom-by-atom? Read the 3-step physics strip below, then keep scrolling for Chapter 2 (Microscopic Atomic Zoom) and Chapter 3 (Interactive Real vs. Fake Split Loupe).
How The Crystal Physics Works (3-Step Flowchart)
Visual Mechanism Breakdown
1. Acid Waters Oxidize Galena & Arsenopyrite
Groundwater weathering lead sulfide (Galena) beside arsenic ores brews concentrated Pb2+, Cl-, and bulky AsO4(3-) arsenate ions.
❌ MYTH: Curved orange Campylite crystals were tumbled or melted into barrel shapes.
✅ FACT: Campylite grows naturally with convex bowed prism sides directly inside untouched Cumbria rock pockets—driven by solid-solution strain between Phosphate and Arsenate!
❌ MYTH: You can tell yellow Mimetite from yellow Pyromorphite reliably just by color.
✅ FACT: Because Pyromorphite and Mimetite share a complete solid-solution series with overlapping yellow-green shades, yellow intermediates often require EDS/Raman lab chemistry to name strictly!
❌ MYTH: Yellow crystals with resinous sheen can always be cleaned with warm vinegar or CLR rust remover.
✅ FACT: Acid dissolves both Mimetite and Pyromorphite while leaching toxic Lead and Arsenic directly into wastewater—NEVER use acid dips on secondary Pb ores!
Chapter 3 of 3 • Interactive Real vs. Fake Split Loupe
Authentic Specimen vs. Fake / Impostor Drag-Loupe
Drag the divider left/right — toggle Probe Mode for forensic lighting, cleavage & bubble inspection.
60-Second Pocket Field Test Checklist
Always test apparent density carefully by heft: Lead Arsenates clock an extraordinary SG 7.1–7.25, making even small walnut-sized specimens feel heavily weighted like solid metal.
Inspect curved Cumbrian Campylite barrels under 10x: look for bulging convex orange hexagons pinched tightly at top/bottom terminations sitting on dark matte manganese oxides.
Check Pingtouling yellow domes under a loupe to confirm micro-crystalline facet sparkle across every grape-like ball rather than painted smooth clay.
Handle cleanly and wash hands thoroughly afterward—Pb5(AsO4)3Cl carries BOTH Lead and Arsenic toxicity!
Collector Caution & Fake Alert: SEVERE LEAD + ARSENIC TOXICITY: Mimetite and Campylite pack BOTH Lead AND Arsenic (Pb5(AsO4)3Cl)! Keep out of reach of children and pets, NEVER scratch-powder dry indoors, NEVER immerse in household acids (dissolves toxic lead/arsenic!), and wash hands cleanly after inspecting raw matrix.
Collector Field Guide & Mineralogy Deep Dive
Locality, Chemistry & Optical Notes
🇬🇧 Dry Gill Cumbria: Home Of 'Campylite'
High across England's misty Caldbeck Fells in Cumbria, the historic Dry Gill Lead Mine exposed dark brown manganese-oxide fractures packed with bloated orange-red curved Campylite barrels—an instantly recognizable 19th-century Victorian British classic!
🇨🇳 Pingtouling Mine: China's Yellow Revolution
Prior to 2005, fine bright yellow Mimetite usually meant sparse little Mexican tufts or rare expensive Tsumeb prisms. Guangdong's Pingtouling pocket suddenly unleashed gleaming egg-yolk botryoidal clusters on jet-black limonite that conquered every mineral museum!
A Phosphate tetrahedron spans ~1.53 Å P-O bonds while Arsenate stretches wider (~1.69 Å As-O). Cramming mismatched building blocks side-by-side inside hexagonal Pb5(XO4)3Cl twists crystal planes gently outward along midsections like wooden staves on a whiskey barrel!
🔬 Why Streak & Density Beat Color Every Time
Yellow Wulfenite, Yellow Barite, Sulfur, Orpiment, and Calcite all mimic Mimetite yellow—yet only Mimetite combines Mohs 3.8 hardness, white streak, and mind-bending SG 7.25 density on hexagonal barrels!
Diagnostic Specimen Comparison Matrix
Quick Laboratory & Collector Reference
Mineral / Control
Formula & System
Key Physical Metric
Diagnostic Tell
Classic Locality
Pingtouling Mimetite
Pb5(AsO4)3Cl | 100% As
Mohs 3.8 | SG 7.25
Egg-yolk botryoids on black iron goethite
Guangdong, China
Cumberland Campylite
Pb5(AsO4,PO4)3Cl | Strain
Mohs 3.5 | SG 7.15
Curved bloated burnt-orange pumpkin barrels
Caldbeck Fells, UK
Tsumeb Mimetite
Pb5(AsO4)3Cl | Gem
Mohs 3.8 | RI 2.15
Clear translucent lemon spires up to 5 cm
Tsumeb, Namibia
Apple Pyromorphite
Pb5(PO4)3Cl | 0% As
Mohs 3.5-4.0 | SG 7.04
Bright apple-green straight/hollow barrels
China / Idaho / France
Hedyphane
Ca2Pb3(AsO4)3Cl
Mohs 4.5 | SG 5.82
Creamy white; warm orange SWUV
Långban / Franklin NJ
Honey Calcite
CaCO3 | Trigonal
Mohs 3.0 | SG 2.71
2.7x lighter! Rhomb cleavage + HCl fizz
Global Carbonate
Frequently Asked Mineralogy Questions
Collector & Lab Answers
Why is Mimetite called 'the imitator' and how does it relate to Pyromorphite?
Breithaupt named Mimetite from Greek 'mimetes' because its Arsenate crystals form a complete solid solution with Phosphate Pyromorphite—often appearing visually identical until checked by chemical/Raman assay.
What causes English Campylite crystals to curve into fat little barrels?
Campylite is a Phosphatian Mimetite (~20–40% Phosphate mixed with larger Arsenate): atomic size mismatch inside the crystal lattice builds internal strain that bends hexagonal prisms into plump curved barrels.
Are Mimetite and Campylite toxic to handle?
Yes—they contain both Lead and Arsenic (Pb5(AsO4)3Cl). They are safe to admire untouched on shelves, but keep away from children/pets, never grind or clean with acids, and always wash hands after handling.
How heavy should a real Mimetite specimen feel compared to yellow Calcite or Fluorite?
Shockingly heavy! Pure Mimetite clocks Specific Gravity ~7.24—more than double Fluorite (3.18) and nearly triple yellow Calcite (2.71).
What makes Pingtouling Chinese Mimetite so distinctive?
Pingtouling Mimetite grows vivid egg-yolk yellow botryoidal spheres built of tiny gleaming prisms resting starkly atop jet-black iron goethite matrix.