Tarnished Black Oxide Coat vs Tin-White Fracture • Concentric Reniform Shells • Safety & Handling Rules (60FPS)
Looking like dull, soot-black volcanic cauliflower lumps on mineral museum shelves, crack open an old Harz Mountains 'Scherbenkobalt' specimen—and fresh broken shells gleam blinding mirror-bright tin-silver for just hours before air tarnishes them bronze-black again! Pure trigonal Native Arsenic (As) crystallizes inside cold hydrothermal silver-cobalt veins in stacked concentric onion-skin spheres, earning German miners' nickname 'Shard Cobalt' alongside crystalline Stibarsen (AsSb) and gleaming Native Antimony! Safely slice digital onion shells, track tarnish oxidation speed, and inspect non-hazardous visual ID checks!
St. Andreasberg German Native Arsenic • Concentric Curved Shells!
Visual ID Signature: Look for stacked half-shells flaking like dark tarnished metallic onion peels with zero sharp cube crystals!
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. Low-Temperature Vein Fluids Deposit Buckled As Layers
In silver-cobalt-nickel hydrothermal veins (~150–250°C), pure uncombined Arsenic precipitates rhythmically in concentric curved micro-crystalline sheets.
2. Fresh Silver-Tin Fractures Tarnish Rapidly In Air
Chip or cleave a dark Scherbenkobalt sphere and pure tin-white metallic glitter shines brightly—only for oxygen and humidity to film it bronze, then dull soot-black.
Pure Native Antimony (Sb)Mirror Tin-White Indefinitely! | SG 6.68
Kidney Hematite (Fe2O3 Contrast)Rust-Proof Hard Black Kidney Balls | Safe!
Quick Field Myth vs. Fact Check
Common Collector Misconceptions
❌ MYTH: Old mineral collectors routinely verify Native Arsenic by tapping it with a hammer to smell garlic.
✅ FACT: DANGEROUS ANACHRONISTIC ADVICE! Never hammer, grind, heat, or sniff Native Arsenic—heating volatilizes invisible, acutely toxic Arsenic Trioxide fumes straight into your lungs! Verify via onion morphology, SG, and safe lab XRF.
❌ MYTH: If an Arsenic specimen turns completely black, the mineral decayed into another rock.
✅ FACT: Only the outermost micron-thick tarnish patina oxidized matte black—every millimeter underneath remains pure glistening silvery trigonal Native Arsenic!
❌ MYTH: Shiny jagged grey metallic chunks sold online as 'raw Antimony/Arsenic' are genuine.
✅ FACT: Many cheap online metallic crystals are ultra-light smelted industrial Silicon (SG 2.33)—check density immediately before trusting shiny unlabeled metalloid shards!
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
NEVER touch bare Native Arsenic without nitrile gloves or store it unboxed on dusty open shelves—seal cleanly inside a clear airtight specimen Perky/acrylic box.
Look for classic concentric curved 'onion-skin' fractures flaking off rounded dull soot-black botryoidal masses (Harz 'Scherbenkobalt').
Separate Antimony from Arsenic by luster & cleavage: Antimony holds persistent mirror-bright tin sheen across broad flat cleavage plates, while Arsenic tarnishes dark matte black across curved shell fractures.
Check heft instantly: genuine Arsenic (SG 5.73) and Antimony (SG 6.68) weigh more than double lightweight smelter Silicon fakes (SG 2.33).
Collector Caution & Fake Alert: STRICT TOXIC MINERAL SAFETY WARNING: Native Arsenic (As) slowly forms powdery surface Arsenic Trioxide (As2O3) patina! NEVER scratch, sand, grind, crush, heat with torches (poisonous arsine/arsenic fumes!), lick, or display unwrapped near food/children! Keep inside sealed clear acrylic display boxes and ALWAYS wash hands thoroughly with soap and cold water after wearing nitrile gloves!
Collector Field Guide & Mineralogy Deep Dive
Locality, Chemistry & Optical Notes
🇩🇪 Why German Miners Named It 'Scherbenkobalt'
In Saxony and the Harz Mountains, miners broke dark rounded Arsenic layers into curved pottery-like shards ('Scherben') mixed alongside silver-nickel-cobalt ores—blaming wicked mine goblins ('Kobolds') when smelter stacks unleashed choking garlic-smelling fumes!
🇯🇵 Japan's Famous Spiky Akatani Spheres
While German veins packed Arsenic tightly into overlapping crusts, Japan's Akatani Mine (Fukui) grew breathtaking detached crystal hedgehogs studded with sharp metallic rhombohedra—ranking among Asia's most iconic native elements.
⚛️ Periodic Column 15: As, Sb & Bi Structural Twins
Arsenic, Antimony, and Bismuth share an unusual buckled-sheet Trigonal R-3m lattice—causing slow metallic conductivity and flaky basal cleavage across the whole family from light toxic As down to non-toxic rainbow Bismuth!
📦 Museum Storage Best Practices (No Silica-Gel Trap!)
Keep Native Arsenic tightly sealed dry at stable room temperature inside clear acrylic boxes clearly tagged 'TOXIC — WASH HANDS IF HANDLED', ensuring children and pets never open specimen cases.
Diagnostic Specimen Comparison Matrix
Quick Laboratory & Collector Reference
Mineral / Control
Formula & System
Key Physical Metric
Diagnostic Tell
Classic Locality
Harz Native Arsenic
As | Trigonal R-3m
Mohs 3.5 | SG 5.73
Dull soot-black curved onion shells; fresh tin fracture
St. Andreasberg, Germany
Akatani Crystal Arsenic
As | Radiating Rhombs
Mohs 3.5 | SG 5.75
Freestanding spiky metallic spheres
Fukui Pref., Japan
Stibarsen (Allemontite)
AsSb | 1:1 Trigonal
Mohs 3.5 | SG 6.20
Natural zebra-banded silver-grey metalloid alloy
Allemont / Varutrask
Native Antimony
Sb | Trigonal R-3m
Mohs 3.3 | SG 6.68
Stays bright mirror tin-white; broad cleavage
Lake George, Canada
Kidney Hematite
Fe2O3 | Trigonal
Mohs 6.0 | SG 5.26
Safe cherry-red streak; scratches brass easily
Cumberland UK (Lookalike)
Smelter Silicon Fake
Si | Diamond Cubic
Mohs 6.5 | SG 2.33
Half weight! Jagged non-tarnishing factory chunks
Industrial Lookalike
Frequently Asked Mineralogy Questions
Collector & Lab Answers
Why is Native Arsenic called 'Scherbenkobalt'?
It is a classic German mining term meaning 'Shard Cobalt': Native Arsenic breaks into curved, onion-peel layered metallic shards that looked dark like cobalt ores and released toxic garlic-scented fumes in medieval silver smelters.
Why do old Native Arsenic specimens look matte black instead of silvery metallic?
Freshly broken Native Arsenic shines bright tin-white, but atmospheric oxygen quickly coats the surface with a thin matte bronze-to-soot-black oxide patina over hours or days.
Is it safe to keep a Native Arsenic mineral specimen in a home collection?
Yes—provided it stays strictly sealed inside an airtight clear display box out of reach of children/pets, is never ground, heated, or licked, and you wear gloves/wash hands thoroughly after touching any loose piece.
How do collectors separate Native Arsenic from Native Antimony without destroying either?
Native Antimony has a higher density (SG 6.68 vs 5.73), retains bright mirror-like silver-tin luster for years with minimal tarnish, and breaks along flat cleavage planes rather than curved concentric onion shells.
Should you ever test Native Arsenic by hitting it with a hammer to smell garlic?
NO! Heating, grinding, or crushing Native Arsenic releases poisonous arsenic dust and fumes—always rely on safe physical inspection, weight, and non-destructive museum records.