Kristal
Opal
Opal • Silika amorf hidrasi (SiO₂·nH₂O) Struktur: bal-balan silika + banyu • Amorf (opal‑A/AG) Mohs ~5–6.5 • SG ~1.98–2.25 Kilap: Vitreous nganti waxy • Pecah: Konkoidal Fenomena: Play‑of‑color (difraksi) Opal...
Opal
Opal • Silika amorf hidrasi (SiO₂·nH₂O) Struktur: bal-balan silika + banyu • Amorf (opal‑A/AG) Mohs ~5–6.5 • SG ~1.98–2.25 Kilap: Vitreous nganti waxy • Pecah: Konkoidal Fenomena: Play‑of‑color (difraksi) Opal...
Moqui
“Moqui marbles” • Konkresi besi-oksida Host: Navajo Sandstone (Jurassic), SW USA Komposisi: Hematit (Fe2O3) ± Goetit ngubengi inti pasir kuarsa Bentuk: Bal • Disk • Donat • Doublet Analog: Dibandhingake...
Moqui
“Moqui marbles” • Konkresi besi-oksida Host: Navajo Sandstone (Jurassic), SW USA Komposisi: Hematit (Fe2O3) ± Goetit ngubengi inti pasir kuarsa Bentuk: Bal • Disk • Donat • Doublet Analog: Dibandhingake...
Moonstone
Moonstone • Feldspar kanthi adularescence Spesies klasik: orthoclase–albite intergrowth (K-feldspar + Na-feldspar) Mohs ~6–6.5 • SG ~2.56–2.60 • Cleavage: loro arah (apik) Optik: RI ~1.518–1.526 • Birefringence ~0.005–0.009 • Fenomena:...
Moonstone
Moonstone • Feldspar kanthi adularescence Spesies klasik: orthoclase–albite intergrowth (K-feldspar + Na-feldspar) Mohs ~6–6.5 • SG ~2.56–2.60 • Cleavage: loro arah (apik) Optik: RI ~1.518–1.526 • Birefringence ~0.005–0.009 • Fenomena:...
Obsidian
Obsidian • Kaca vulkanik (mineraloid) Kimia: Lelehan sugih silika (rhyolitik) • SiO₂ ~70–78% Mohs ~5–5.5 • SG ~2.3–2.45 Pecah: Konkoidal (tajam kaya silet) Fenomena/Varietas: Salju • Kilap • Pelangi •...
Obsidian
Obsidian • Kaca vulkanik (mineraloid) Kimia: Lelehan sugih silika (rhyolitik) • SiO₂ ~70–78% Mohs ~5–5.5 • SG ~2.3–2.45 Pecah: Konkoidal (tajam kaya silet) Fenomena/Varietas: Salju • Kilap • Pelangi •...
Lepidolite
Lepidolit • Mica sugih lithium (trioctahedral) Formula kira-kira: K(Li,Al,Rb)3(Al,Si)4O10(F,OH)2 Sistem kristal: Monoklinik (piringan pseudo-heksagonal) Mohs ~2.5–3 • SG ~2.8–2.9 Pecahan: Sampurna ing {001} (lembaran mica) Palet: Lilac • Lavender •...
Lepidolite
Lepidolit • Mica sugih lithium (trioctahedral) Formula kira-kira: K(Li,Al,Rb)3(Al,Si)4O10(F,OH)2 Sistem kristal: Monoklinik (piringan pseudo-heksagonal) Mohs ~2.5–3 • SG ~2.8–2.9 Pecahan: Sampurna ing {001} (lembaran mica) Palet: Lilac • Lavender •...
Magnesite
Magnesite • MgCO₃ — magnesium karbonat (klompok kalsit) Sistem kristal: Trigonal (rhombohedral) • Cleavage: rhombohedral sempurna Mohs: ~3.5–4.5 • SG: ~3.0–3.1 • Kilap: vitreous nganti pudar (asring kapur) Perilaku: fizz...
Magnesite
Magnesite • MgCO₃ — magnesium karbonat (klompok kalsit) Sistem kristal: Trigonal (rhombohedral) • Cleavage: rhombohedral sempurna Mohs: ~3.5–4.5 • SG: ~3.0–3.1 • Kilap: vitreous nganti pudar (asring kapur) Perilaku: fizz...