87°/93° Square Chains vs 56°/124° Diamond Chains • Augite vs Hornblende • Jadeite vs Nephrite (60FPS)
Ask any geology student their #1 field nightmare: holding two shiny jet-black rocks and guessing whether it is Pyroxene (Augite) or Amphibole (Hornblende)! Strike the crystal cross-section down the C-axis to expose 87°/93° Single-Chain Boxes vs 56°/124° Double-Chain Diamonds—the exact same geometric rule separating Jadeite Jade from Nephrite!
Single-Chain Augite Pyroxene (XY(Si,Al)2O6): Cleavage planes step nearly square at 87° and 93°—stubby 8-sided barrel crystals!
Wait — Did You Know?Twist a dark lava phenocryst under sunlight with a 10x lens: if the two shiny step cleavages lock together almost at a square corner (87° and 93°) on a short chunky 8-sided barrel, you're holding dry high-temperature Augite Pyroxene!
Select Mineral or Control Specimen (8 Profiles)
Click crystal cross-section or slide Chain Width, Cross-Angle & Mohs Scratch to split Augite from Hornblende!
Pocket Protractor Trick: Line a sheet corner (90°) up to broken Augite cleavage—it fits the paper corner nearly flush (3° off), whereas Hornblende leaves a huge 34° wedge gap!
Why does the crystal behave like that? Read the 3-step physics below, then keep scrolling to unlock Chapter 2 (Microscopic Atomic Zoom) and Chapter 3 (Interactive Real vs. Fake Loupe).
How The Crystal Physics Works (3-Step Flowchart)
Visual Mechanism Breakdown
1. Count How Wide Each Silica Spine Grows (1x vs 2x)
Magma temperature and water dictate whether SiO4 pyramids link into slim single chains (SiO3 = Pyroxene) or zip together sideways into wide double ribbons (Si4O11 = Amphibole).
2. Weak Metal-Ion Seams Between Chains Snap Cleanly
Strong covalent Si-O spines refuse to break horizontally; instead, hammers crack crystals cleanly BETWEEN parallel spines along weaker Ca/Mg/Fe cross-links!
3. Cross-Section Brickwork Locks In Exact 87° vs 56° Math
Single chains pack almost square (87°/93° cross-rectangles), whereas wide flat double ribbons brick-stack staggered diagonally—forcing crystal cleavage walls permanently to 56° and 124°!
Chapter 2 of 3 • Microscopic Atomic Lattice Zoom
Inside The Lattice: Augite ((Ca,Na)(Mg,Fe,Al)(Si,Al)2O6)
Black Biotite Mica (Sheet Basal Split)1 Single 180° Flaky Sheet Plane | Mohs 2.5 (Peels w/ Nail!)
Quick Field Myth vs. Fact Check
Common Collector Misconceptions
❌ MYTH: You need an X-ray lab or polarizing microscope to tell black Augite from black Hornblende.
✅ FACT: Any $5 10x pocket loupe works in bright sunlight—tilt a freshly fractured piece until two flat shiny faces flash (near-90° box = Pyroxene; sharp 56° wedge / obtuse 124° blink = Amphibole)!
❌ MYTH: All dark elongated black needles inside granite or schist must be Hornblende.
✅ FACT: Black Tourmaline (Schorl), Stibnite (soft metallic), and Allanite (radioactive epidote) mimic black needles—ONLY Amphibole shows shiny stepped 56°/124° cleavage flashes!
❌ MYTH: Jadeite and Nephrite are just geographical nicknames for one green stone.
✅ FACT: They belong to two completely separate mineral supergroups (Pyroxene vs Amphibole) with distinct SG (3.34 vs 2.95), RI (1.66 vs 1.61), and crystal structure!
Chapter 3 of 3 • Interactive Real vs. Fake Split Loupe
Authentic vs. Common Fake / Impostor Drag-Loupe
Drag the gold divider left/right — compare natural diagnostic optics vs synthetic bubbles or dye cracks.
Run a pocket knife edge across clean black prisms: zero flat cleavage flashes + rounded 3-sided belly + Mohs 7.5 (doesn't scratch cleanly) identifies Schorl Tourmaline instead!
Check specific gravity (SG) on questionable carved Jade: dense Burmese Jadeite (SG 3.34) drops fast in Methylene Iodide (3.32), while lighter Nephrite (SG 2.95) floats right on top!
Look at rock host context cleanly: dry black Hawaiian basalt phenocrysts favor Augite, whereas pale pink granite pegmatites or snowy quartz dikes host wet Hornblende!
Collector Caution & Fake Alert: Careful buying 'Black Tourmaline', 'Black Kyanite', or 'Black Hornblende' specimens mixed online: cheap shiny tumbled Black Obsidian (conchoidal glass, Mohs 5.5) and dark Anthracite Coal (ultra-light SG 1.4!) masquerade constantly in mystery bags!
Collector Field Guide & Mineralogy Deep Dive
Scientific Reference Notes
📐 How Bragg & Chain Width Predict Every Split Before Breaking
Long before X-ray crystallography solved silica chains in 1929 (Warren & Bragg), mineralogists puzzled over why Diopside and Tremolite shared twin cleavages 31 degrees apart (87° vs 56°)—turns out 1x vs 2x chain width ratio literally sets the brickwork triangle geometry!
🌋 Bowen's Reaction Thermometer Inside Rocks
When water-poor magma cools (~1100°C), dry Augite Pyroxene crystallizes first; once cooling residual melt concentrates dissolved ocean water (H2O), existing Augite rims literally dissolve and regrow outer jackets of Hornblende Amphibole (800°C)!
💀 The Blue & Brown Asbestos Secret (Crocidolite vs Chrysotile)
Several double-chain Amphiboles (Riebeckite = Crocidolite blue, Amosite brown) crystallize into deadly straight inflexible lung needles—far more biopersistent than curly serpentine Chrysotile!
💜 Hiddenite & Kunzite: One Trace Element Apart
Identical monoclinic Lithium Pyroxene (Spodumene) shifts from pure electric lilac (Kunzite = Mn3+) to intense emerald-green (Hiddenite = Cr3+/V3+) in North Carolina pegmatites!
Diagnostic Specimen Comparison Table
Quick Laboratory & Field Reference
Mineral / Control
Chemistry / System
Property
Diagnostic Signal
Classic Source
Augite (Pyroxene)
Single SiO3 (Dry)
87° / 93° Blocky
Mohs 5.5-6 | 8-sided barrel
Basalt / Gabbro
Hornblende (Amphibole)
Double Si4O11 (OH)
56° / 124° Diamond
Mohs 5-6 | 6-sided splinter
Granite / Diorite
Jadeite Jade
NaAlSi2O6 Pyroxene
87° Interlocking
SG 3.34 | Dimpled orange-peel
Myanmar / Guatemala
Nephrite Jade
Actinolite Amphibole
56° Felted Mats
SG 2.95 | Greasy luster
BC Canada / Siberia
Kunzite (Spodumene)
LiAlSi2O6 Pyroxene
87° + Parting!
Mohs 6.5-7 | Strong C-violet
Pala CA / Afghanistan
Black Schorl
Ring Borosilicate
ZERO Cleavage!
Mohs 7.5 | Curved glass break
Pegmatite Impostor
Frequently Asked Mineralogy Questions
Collector & Lab Answers
How do I easily remember Pyroxene 87° vs Amphibole 56°?
Why don't black Hornblende crystals always look like needles?
Only broken cross-sections viewed straight down the long C-axis clearly expose the 56°/124° diamond angle; looking at the flat side merely shows shiny parallel stripes (cleavage traces).
Are Jadeite and Nephrite chemically the same stone?
No! Burmese Jadeite is a dense Sodium-Aluminum Pyroxene (NaAlSi2O6, SG 3.34), while classic carved Nephrite is a Calcium-Magnesium-Iron Amphibole (Tremolite-Actinolite, SG 2.95).
Is every shiny black elongated mineral in a hand specimen either Pyroxene or Amphibole?
No—Black Schorl Tourmaline (rounded triangle, Mohs 7.5, zero cleavage), Stibnite (metallic lead-gray, Mohs 2), and Epidote (pistachio-black, 1 cleavage) are common lookalikes.