68% Metallic Silver Content • RI 3.09 Higher Than Diamond • Reversible Surface Silver Tarnish (60FPS)
Deep inside dark Chilean and German silver shafts sat crystals glowing clearer crimson than Burmese Ruby—yet packing 65% pure Silver by weight! Miners called transparent trigonal Proustite (Ag3AsS3)'Ruby Silver', only to watch proud shelf displays glaze permanently into dull graphite-silver tarnish within months. Expose the specimen to daylight photons or slide protective vault doors shut!
Mechanism: Ag+ Ions Migrate Under Photons Plating Metallic Ag0 Haze
Proustite (Ag3AsS3): Electric flame-scarlet translucent crystals beating Diamond's RI (3.09 vs 2.42) until daylight tarnishes surface silver!
Wait — Did You Know?Museum drawers holding 19th-century Chilean Chañarcillo Proustite open only 30 seconds at a time—like unfixed camera film, silver cations migrate straight to crystal skin under room bulbs!
Select Specimen or Control Sample (8 Profiles)
Click any Ruby Silver ore or lookalike to test silver content, RI sparkle, and photochemical blackening:
Refractive Index & StreakRI 2.79-3.09! | Vermilion Streak
Dark-Vault Preservation StateKEEP IN PITCH DARKNESS!
Film Chemistry Kin: Black-and-white silver halide photography literally exploits this exact same Ag+ light-darkening physics!
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. Epithermal Silver Veins Freeze Ag3AsS3
Cool hydrothermal brines precipitate trigonal pyramids containing 65% pure metallic Silver interlaced with Arsenic-Sulfur bonds—giving adamantine RI above 3.0!
2. Light Photons Knock Electrons Onto Ag+ Ions
Just like classic 35mm black-and-white photographic silver film, visible & UV photons reduce mobile Ag+ cations at the surface straight into opaque Ag0 silver metal grains.
3. UV-Filtered Dark Vaults Lock Glow For Centuries
Blocking ambient room light keeps historic Chañarcillo and Schneeberg crystals burning neon crimson for generations instead of going matte lead-gray.
Chapter 2 of 3 • Microscopic Atomic Lattice Zoom
Inside The Lattice: Translucent Light Ruby Silver (Proustite)
Trigonal R3c Pyramidal AsS3/SbS3 Units Linked By Spiral S-Ag-S Bridges
Ruby Silver Sulfosalt RI & Light-Stability Comparison Scale
Comparative Mineral Property Scale
Proustite (Light Ruby Silver)65.4% Ag | SG 5.57 | RI 3.09! | EXTREME Light Risk
Pyrargyrite (Dark Ruby Silver)59.8% Ag | SG 5.85 | RI 3.08 | Moderate Light Risk
Cuprite Control (Cu2O)SG 6.14 | RI 2.85 | Cubic | 100% Light Stable!
Xanthoconite (Ag3AsS3 Dimorph)SG 5.54 | RI 3.0 | Monoclinic Yellow-Amber
Almandine Garnet ControlSG 4.1 | RI 1.79 | Mohs 7.0 Hard (Not Sulfosalt)
Quick Field Myth vs. Fact Check
Common Collector Misconceptions
❌ MYTH: Red Proustite only blackens in humid coastal air because sulfur tarnishes just like sterling spoons.
✅ FACT: Actually, dry vacuum won't save it! Light photons themselves drive internal silver-ion photoreduction directly on crystal faces even inside argon-sealed ampoules.
❌ MYTH: Darkening means the whole Proustite crystal rotted into worthless dust forever like Pyrite.
✅ FACT: Unlike Pyrite rot or Realgar crumble, Proustite keeps its sharp crystal shape intact underneath a paper-thin surface skin of blackened metallic silver!
❌ MYTH: Dunking a tarnished Proustite cluster in commercial liquid jewelry 'Silver Dip' makes it ruby red again.
✅ FACT: NEVER DO THIS! Chemical dips strip micro-facets into dull chalky frosted mush and expose reactive fresh silver that blackens twice as fast afterward.
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
Examine bright-red metallic ore prisms gently under brief dim flashlight: genuine Proustite shows crisp trigonal striations and blood-red flash at broken edges (vs cubic Cuprite octahedra).
Test streak on a tiny inconspicuous back crystal: Proustite streaks brilliant scarlet-vermilion, Pyrargyrite streaks darker cherry-plum, and Cuprite streaks brownish-red.
Check density and softness: Ruby Silver feels very heavy (SG 5.57–5.85) yet scratches effortlessly at Mohs 2.5—instant proof against Mohs 7 Garnet.
Care & Storage Rule: Place Proustite inside opaque black-cardboard or velvet light-proof specimen drawers, never on open sunlit window shelves!
Collector Caution & Fake Alert: Proustite (Ag3AsS3) packs ~15% toxic Arsenic alongside Silver, while Pyrargyrite carries Antimony—AND intense UV or incandescent lights rapidly oxidize bright cherry ruby faces into dull opaque silver-gray film! Store strictly inside velvet-lined blackout cabinets and NEVER expose to ammonia/bleach silver dips that etch faces irreversibly.
Collector Field Guide & Mineralogy Deep Dive
Locality, Chemistry & Optical Notes
🇨🇱 Chañarcillo's Legendary 1832 Bonanza
When muleteer Juan Godoy stumbled upon exposed silver outcrops south of Copiapó in Chile's Atacama Desert, Chañarcillo's pockets unleashed decimeter-long blood-red transparent Proustite spears that still anchor museum vaults in Paris, London, and Washington.
🇩🇪 Schneeberg's Saxon Mining Heritage
Deep in Germany's Erzgebirge cobalt-silver mines, medieval miners pulled gleaming scarlet 'Rothgültigerz' ('red valid silver ore')—learning painfully by candlelight why unboxed museum specimens dulled gray in sunlit glass cabinets.
📷 Shared Physics With Kodak Silver Film
Traditional film photography suspended Silver Bromide microcrystals in gelatin because photons convert colorless Ag+ ions into dark metallic Ag0 grains—Proustite executes that exact chemical magic naturally inside its own crystal skin!
💎 Why Rare Faceted Ruby Silvers Stay In Vaults
With refractive index soaring to 3.09 (beating Diamond's 2.417), faceted Proustite displays uncanny metallic-crimson fire—yet can never be displayed under bright showroom cases!
Diagnostic Specimen Comparison Matrix
Quick Laboratory & Collector Reference
Mineral / Control
Formula & System
Key Physical Metric
Diagnostic Tell
Classic Locality
Proustite
Ag3AsS3 | Trigonal
65.4% Ag | SG 5.57 | RI 3.09
Bright scarlet streak; blackens fastest in light
Chañarcillo, Chile
Pyrargyrite
Ag3SbS3 | Trigonal
59.8% Ag | SG 5.85 | RI 3.08
Deep crimson-plum streak; slower light tarnish
Freiberg / Guanajuato
Xanthoconite
Ag3AsS3 | Monoclinic
65.4% Ag | SG 5.54 | Orange Plates
Honey-orange wafer polymorph on Proustite
Schneeberg / Chile
Miargyrite
AgSbS2 | Monoclinic
36.7% Ag | SG 5.25 | Mohs 2.5
Iron-black crystal w/ vivid cherry-red streak
Bolivia / Germany
Cuprite Control
Cu2O | Cubic
SG 6.14 | Mohs 3.5-4.0 | Stable
Cubic octahedra; brownish-red streak; light-safe
Onganja, Namibia
Garnet Impostor
Fe3Al2Si3O12 | Cubic
SG 4.1 | RI 1.79 | Mohs 7.0
Scratches steel; far lighter; zero light tarnish
Worldwide Silicate
Frequently Asked Mineralogy Questions
Collector & Lab Answers
Why does Proustite 'Ruby Silver' turn black on display shelves?
Visible and UV light photons cause mobile silver ions (Ag+) near the crystal surface to gain electrons and form an opaque black/gray coating of metallic silver/silver sulfide—the same core photoreduction behind vintage black-and-white film.
What is the difference between Proustite and Pyrargyrite?
Both are 'Ruby Silver' with identical trigonal crystal structure, but Proustite contains Arsenic (bright scarlet color & scarlet streak, SG 5.57) whereas Pyrargyrite contains Antimony (darker plum-red color & cherry-purple streak, SG 5.85).
How should collectors store Proustite specimens?
Keep Proustite completely away from sunlight and bright display bulbs—inside sealed, UV-free opaque drawers or covered boxes—only opening briefly under cool LED inspection.
Can a tarnished black Proustite crystal be restored safely?
Cleaning with abrasive silver polishes or acidic silver dips permanently ruins delicate Mohs 2.5 crystal faces. Serious museum curators leave mild age patina intact or consult professional conservators.
Is Proustite actually made of real silver?
Yes! Pure Proustite is 65.4% elemental Silver by weight—historic mines smelted hundreds of tons of ruby silver directly into silver bullion.