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Chromite — FeCr2O4, a black iron-chromium oxide, the main chromium ore (stainless steel, chrome, refractories). Forms in peridotite and layered intrusions (Bushveld).

Mohs ~5.5, metallic. Spin ↓

Specimen image: AI-generated.
https://apps.apple.com/us/app/rockspin/id6747876962
#Chromite #RockSpin
AI-generated specimen image of chromite: a black, metallic cluster of sharp octahedral crystals on a plain light-grey background, with the RockSpin logo in the corner.
November 5, 2026 at 8:15 PM
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Digenite — Cu9S5, a blue-black copper sulfide and a real copper ore. It forms where copper deposits weather and get enriched, often alongside chalcocite.

Mohs 2.5–3, metallic. Spin ↓

Specimen image: AI-generated.
https://apps.apple.com/us/app/rockspin/id6747876962
#Digenite #RockSpin
AI-generated specimen image of digenite: a rounded, blue-black, metallic granular mass of tiny glittering crystals on a plain light-grey background, with the RockSpin logo in the corner.
November 3, 2026 at 8:15 PM
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Dravite — NaMg3Al6(Si6O18)(BO3)3(OH)4, the brown, magnesium-rich member of the tourmaline family. It grows in metamorphosed marbles and magnesium-rich schists.

Mohs 7–7.5. Spin ↓

Specimen image: AI-generated.
https://apps.apple.com/us/app/rockspin/id6747876962
#Dravite #RockSpin
AI-generated specimen image of dravite: a cluster of brown, translucent, striated prismatic tourmaline crystals on a plain light-grey background, with the RockSpin logo in the corner.
November 2, 2026 at 8:19 PM
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Iron — native Fe, a steel-grey, strongly magnetic metal. Rare as a native mineral on Earth's surface; most is found in meteorites or in basalts that met coal. Body-centred cubic.

Mohs 4–5. Spin ↓

Specimen image: AI-generated.
https://apps.apple.com/us/app/rockspin/id6747876962
#Iron #RockSpin
AI-generated specimen image of native iron: a lumpy, steel-grey metallic mass covered in small glinting crystal faces on a plain light grey background, with the RockSpin logo in the corner.
October 31, 2026 at 7:16 PM
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Aragonite — CaCO3, calcite's chemistry in a denser orthorhombic structure. It builds pearls, nacre and many shells, and grows in caves and hot springs.

Mohs 3.5–4. Spin ↓

Specimen image: AI-generated.
https://apps.apple.com/us/app/rockspin/id6747876962
#Aragonite #RockSpin
AI-generated specimen image of aragonite: a cluster of white to colourless, translucent six-sided columnar crystals on a plain grey background, with the RockSpin logo in the corner.
November 1, 2026 at 8:16 PM
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Magnesite — MgCO3, a calcite-group carbonate: usually white, compact and porcelain-like. Heated, it turns into magnesia (MgO) for refractory bricks.

Mohs 3.5–4.5. Spin ↓

Specimen image: AI-generated.
https://apps.apple.com/us/app/rockspin/id6747876962
#Magnesite #RockSpin
AI-generated specimen image of magnesite: a rounded, compact white lump with a rough, porcelain-like surface and a faint glossy sheen on a plain grey background, with the RockSpin logo in the corner.
October 30, 2026 at 7:18 PM
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Bismuth — Bi, a native semimetal: soft, heavy and silvery with a pinkish tint. Rainbow "hopper" crystals are lab-grown; the colours come from a thin oxide film.

Mohs 2–2.5. Spin ↓

Specimen image: AI-generated.
https://apps.apple.com/us/app/rockspin/id6747876962
#Bismuth #RockSpin
AI-generated specimen image of native bismuth: a rounded cluster of blocky, silvery metallic crystals with a faint pinkish tint and rough, stepped faces on a plain light grey background, with the RockSpin logo in the corner.
October 29, 2026 at 7:23 PM
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Wavellite — Al₃(PO₄)₂(OH,F)₃·5H₂O, a hydrated aluminum phosphate famous for its radiating green "starburst" sprays.

Green to yellow-green, glassy; Mohs 3.5–4. Spin ↓

Specimen image: AI-generated.
https://apps.apple.com/us/app/rockspin/id6747876962
#Wavellite #RockSpin
AI-generated specimen image of wavellite: a rounded cluster of radiating, translucent pale-green crystal sprays on a plain light grey background, with the RockSpin logo in the corner.
October 28, 2026 at 7:17 PM
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Annite — KFe₃AlSi₃O₁₀(OH)₂, the iron-rich end-member of the biotite micas, a dark sheet silicate of igneous & metamorphic rocks.

Black to dark brown; peels into thin flexible sheets. Spin ↓

Specimen image: AI-generated.
https://apps.apple.com/us/app/rockspin/id6747876962
#Annite #RockSpin
AI-generated specimen image of annite: a rounded rosette of stacked, translucent brown hexagonal mica plates with a pearly sheen on a plain light grey background, with the RockSpin logo in the corner.
October 27, 2026 at 7:23 PM
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Titanite (sphene) — CaTiSiO₅, a Ca–Ti nesosilicate & common accessory mineral in igneous & metamorphic rocks, used for U–Pb dating.

Wedge-shaped, adamantine, yellow/brown/green; Mohs 5–5.5. Spin ↓

Specimen image: AI-generated.
https://apps.apple.com/us/app/rockspin/id6747876962
#Titanite #RockSpin
AI-generated specimen image of titanite (sphene): a cluster of glassy, translucent brown wedge-shaped crystals on a plain light grey background, with the RockSpin logo in the corner.
October 25, 2026 at 7:20 PM
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Pyroxmangite — (Mn,Fe)SiO₃, a pink pyroxenoid related to rhodonite. It forms in metamorphosed Mn-rich rocks; its SiO₄ chains repeat every 7 tetrahedra.

Pink to brown-red, Mohs 5.5–6. Spin ↓

Specimen image: AI-generated.
https://apps.apple.com/us/app/rockspin/id6747876962
#Pyroxmangite #RockSpin
AI-generated specimen image of pyroxmangite: a cluster of translucent pink, bladed crystals on a plain light grey background, with the RockSpin logo in the corner.
October 24, 2026 at 7:16 PM
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Dolomite — CaMg(CO₃)₂, a carbonate that builds mountain ranges. It forms when Mg-rich fluids alter limestone; used as aggregate, stone and a Mg source.

Pearly saddle rhombs, Mohs 3.5–4. Spin ↓

Specimen image: AI-generated.
https://apps.apple.com/us/app/rockspin/id6747876962
#Dolomite #RockSpin
AI-generated specimen image of dolomite: a cluster of white, pearly, curved saddle-shaped crystals on a plain grey background, with the RockSpin logo in the corner.
October 23, 2026 at 7:19 PM
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Huntite — CaMg₃(CO₃)₄, an earthy, chalk-white carbonate formed where Mg-rich waters alter dolomite, often in caves. Ancient Egyptian white pigment; now fire-retardant filler.

Mohs 1–2. Spin ↓

Specimen image: AI-generated.
https://apps.apple.com/us/app/rockspin/id6747876962
#Huntite #RockSpin
AI-generated specimen image of huntite: a rough, chalk-white earthy lump on a plain grey background, with the RockSpin logo in the corner.
October 22, 2026 at 7:14 PM
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Cuprite — Cu₂O, a deep red copper oxide ("ruby copper") that forms in the oxidized zone of copper deposits; a classic copper ore.

Adamantine to submetallic, Mohs 3.5–4. Spin ↓

Specimen image: AI-generated.
https://apps.apple.com/us/app/rockspin/id6747876962
#Cuprite #Minerals #RockSpin
AI-generated specimen image of cuprite: a cluster of glassy deep-red octahedral crystals on a plain light grey background, with the RockSpin logo in the corner.
October 21, 2026 at 7:16 PM
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Jarosite — KFe₃(SO₄)₂(OH)₆, a yellow-brown iron sulfate that forms when pyrite weathers in acidic water. Opportunity found it on Mars.

Vitreous to resinous, Mohs ~2.5–3.5. Spin ↓

Specimen image: AI-generated.
https://apps.apple.com/us/app/rockspin/id6747876962
#Jarosite #Minerals #RockSpin
AI-generated specimen image of jarosite: a rough cluster of small glassy honey-yellow to amber-brown crystals on a plain light grey background, with the RockSpin logo in the corner.
October 20, 2026 at 7:20 PM
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Jacobsite — MnFe₂O₄, a cubic spinel-group oxide from Mn-rich skarns and metamorphosed manganese deposits.

Black, metallic to submetallic, Mohs ~5.5–6.5. Spin ↓

Specimen image: AI-generated.
https://apps.apple.com/us/app/rockspin/id6747876962
#Jacobsite #Minerals #RockSpin
AI-generated specimen image of jacobsite: a black metallic manganese-iron oxide crystal cluster on a plain grey background, with the RockSpin logo in the corner.
October 19, 2026 at 4:25 PM
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RockSpin 앱 둘러보기 🪨
암석 표본을 360° 회전하고, 박편은 PPL과 XPL을 오가며 관찰해 보세요.

A quick walk through RockSpin: rotate specimens a full 360° and switch thin sections between PPL and XPL.

https://apps.apple.com/us/app/rockspin/id6747876962
October 18, 2026 at 8:34 PM
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Thermonatrite — Na₂CO₃·H₂O, sodium carbonate with one water. It crusts soda lakes and arid soils, or forms as natron dries out.

Colorless to white, vitreous, Mohs 1–1.5. Spin ↓

Specimen image: AI-generated.
https://apps.apple.com/us/app/rockspin/id6747876962
#Thermonatrite #Minerals #RockSpin
AI-generated specimen image of thermonatrite: a white, sugary cluster of small glassy sodium carbonate crystals on a plain grey background, with the RockSpin logo in the corner.
October 17, 2026 at 7:22 PM
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Kutnohorite — CaMn(CO₃)₂, a trigonal dolomite-group carbonate (R-3): Ca/Mn layers ideally alternate. Named for Kutná Hora, Czechia.

White to rose-pink, vitreous, Mohs 3.5–4. Spin ↓

Specimen image: AI-generated.
https://apps.apple.com/us/app/rockspin/id6747876962
#Kutnohorite #Minerals #RockSpin
Kutnohorite specimen: white to pale pink botryoidal carbonate aggregate on a grey background (AI-generated image), RockSpin watermark
October 16, 2026 at 7:19 PM
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Fluorapatite — Ca₅(PO₄)₃F, hexagonal apatite (P6₃/m). Main industrial P for fertilizer; F end-member vs bone hydroxylapatite.

Green–blue–yellow–violet, vitreous, Mohs 5. Spin below.

Specimen image: AI-generated.
https://apps.apple.com/us/app/rockspin/id6747876962
#Fluorapatite #Minerals #RockSpin
Fluorapatite specimen (AI-generated image), RockSpin watermark
October 15, 2026 at 7:18 PM
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Leucite — KAlSi₂O₆, a feldspathoid of potassium-rich, silica-poor lavas (Vesuvius). Its "cubic" crystals go tetragonal on cooling.

White–grey, vitreous, Mohs 5.5–6.
Spin below.

Specimen image: AI-generated.
https://apps.apple.com/us/app/rockspin/id6747876962
#Leucite #Minerals #RockSpin
Leucite specimen (AI-generated image), RockSpin watermark
October 14, 2026 at 9:19 PM
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Vermiculite — (Mg,Fe,Al)₃(Si,Al)₄O₁₀(OH)₂·4H₂O, a weathered mica that holds water. Heated, it puffs into worm-like strands.

Bronze-brown, pearly, Mohs 1.5–2.
Swipe for the spin.

Specimen image: AI-generated.
https://apps.apple.com/us/app/rockspin/id6747876962
#Vermiculite #Minerals #RockSpin
Vermiculite specimen: stacked bronze-brown mica-like flakes (AI-generated image)
October 13, 2026 at 2:06 AM
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Marcasite — FeS₂, an iron sulfide with pyrite's formula but orthorhombic crystals. Forms in cool, acidic shale and coal.

Pale bronze-yellow, metallic, Mohs 6–6.5.
Swipe for the spin.

Specimen image: AI-generated.
https://apps.apple.com/us/app/rockspin/id6747876962
#Marcasite #Minerals #RockSpin
Marcasite specimen (AI-generated image), RockSpin watermark
October 11, 2026 at 2:21 PM
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Manganosite — MnO, manganese(II) oxide. Cubic rocksalt-type; green to black. Rare in reducing Mn deposits.

Specimen image: AI-generated.
https://apps.apple.com/us/app/rockspin/id6747876962
#Manganosite #Minerals #RockSpin
Manganosite specimen (AI-generated image), RockSpin
October 7, 2026 at 1:39 PM
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Cassiterite — SnO₂, primary tin ore. Brown–black, adamantine–greasy, Mohs ~6–7; dense (~7).

Specimen image: AI-generated.
https://apps.apple.com/us/app/rockspin/id6747876962
#Cassiterite #Minerals #RockSpin
Cassiterite specimen (AI-generated image), RockSpin
October 5, 2026 at 9:58 PM