Hematite — The Metallic Classic with a Ruby‑Red Secret
Hematite is the tuxedo of iron minerals: cool graphite‑to‑steel sheen on the outside, deep red‑brown on the inside. Scratch it on unglazed tile and that rich red streak appears—no, it’s not magic; it’s iron oxide saying hello. From shimmering “specularite” plates to velvety botryoidal “kidney ore,” hematite is at once industrial legend and jewelry favorite. (Bonus: it won’t turn your fingers rusty—that’s not how chemistry works.)
Identity & Naming 🔎
From “blood” to brilliance
The name hematite traces to the Greek haima (“blood”)—a nod to its reddish streak and ancient use as red pigment. As a gem material, it’s celebrated for a mirror‑like metallic polish on cabochons and beads.
Forms & nicknames
- Specularite — sparkling, micaceous plates (very photogenic).
- Kidney ore — botryoidal, velvety masses with rounded lobes.
- Oolitic hematite — tiny iron‑rich spheres cemented in layers.
- Martite — hematite pseudomorph after magnetite, preserving octahedral shapes.
How It Forms 🧭
Banded iron heritage
Many hematite deposits come from ancient banded iron formations (BIFs): rhythmic layers of silica and iron laid down in Precambrian seas. Later metamorphism upgraded them into today’s iron ores and lapidary material.
Weathering & replacement
Near the surface, iron‑bearing minerals like magnetite or siderite oxidize into hematite. This can coat rocks with a rust‑red film (desert varnish) or build solid botryoidal masses in cavities.
Hydrothermal mirrors
In veins and metamorphic zones, fluids deposit hematite as specular plates with bright metallic faces—the “mirrors” beloved by collectors and photographers.
Recipe: iron + oxygen + time. Adjust temperature/fluids → choose your texture: velvet (botryoidal) or mirror (specular).
Palette & Texture Vocabulary 🎨
Palette
- Steel/graphite grey — classic metallic cabochons and plates.
- Gunmetal — satin metallic on botryoidal surfaces.
- Reddish‑brown — earthy massive or weathered surfaces.
- “Ruby” streak — the diagnostic powder color.
The surface gloss ranges from mirror‑bright to satiny or earthy depending on habit and grain size.
Texture words
- Kidney lobes — rounded, overlapping domes with fine micro‑wrinkles.
- Micaceous sparkle — glittery reflections from stacked plates.
- Oolitic — pinhead spheres in cross‑section, like poppy seeds in bread.
- Pseudomorph edges — magnetite‑shaped but hematite‑composed (martite).
Photo tip: Metallic hematite loves one small point light for crisp speculars plus a soft fill to keep blacks rich, not blown out.
Physical & Optical Details 🧪
| Property | Typical Range / Note |
|---|---|
| Chemistry | Fe₂O₃ (iron(III) oxide) |
| Crystal system / Habit | Trigonal; massive, botryoidal, micaceous plates, tabular/rhombohedral crystals |
| Hardness (Mohs) | ~5.5–6.5 (cabochons resist daily scuffs but mind harder neighbors) |
| Specific gravity | ~5.2–5.3 — pleasantly heavy in the hand |
| Cleavage / Fracture | No prominent cleavage; fracture uneven to sub‑conchoidal |
| Luster | Metallic to sub‑metallic (specularite); dull/earthy when massive and fine‑grained |
| Streak | Red‑brown (diagnostic even for silver‑black specimens) |
| Magnetism | Usually weak to none; can be weakly magnetic if fine‑grained, heated, or intergrown with magnetite |
| Conductivity | Poor electrical conductor despite metallic look |
| Treatments | Polish enhancement (waxes/oils) common; “magnetic hematite” jewelry is typically a sintered ferrite/glass‑bonded iron oxide imitation |
Under the Loupe 🔬
Specular sparkle
In “specularite,” look for stacked, reflective plates that glint like graphite flakes. Edges are sharp, surfaces mirror‑bright under raking light.
Kidney ore skin
Botryoidal masses show terraced micro‑growth and soft, satiny luster. Tiny shrinkage cracks between lobes are common and natural.
Martite geometry
Octahedral outlines with hematite interiors. Under magnification, faces look duller than true magnetite and the streak stays red‑brown.
Look‑Alikes & Mix‑ups 🕵️
Magnetite
Also black metallic iron oxide, but typically strongly magnetic and has a black streak (not red). Crystals commonly octahedral.
Goethite / limonite
Brownish to black iron oxyhydroxides; can be botryoidal. Streak is brown‑yellow, luster often less “mirror” than hematite.
Ilmenite
Iron‑titanium oxide; metallic black with black‑grey streak, SG slightly lower than hematite. Common in heavy sand concentrates.
Tumbled imitations
“Magnetic hematite” beads are generally synthetic ferrites. Uniform magnetism and glassy molded facets give them away.
Galena
Lead sulfide—very heavy with bright metallic luster but leaves a grey streak and forms cubic crystals; much softer (easily scratches).
Quick checklist
- Feels heavy for size? ✔ (SG ~5.2).
- Non‑magnetic or only weakly so? ✔
- Streak tile says red‑brown? That’s hematite.
Localities & Uses 📍
Where it shines
Major hematite occurs in Brazil (Minas Gerais), the Lake Superior region of the USA (Michigan & Minnesota), Australia (Pilbara), UK (Cumbria), Spain (Rio Tinto), Morocco, and many more iron districts worldwide.
What it’s used for
Primarily an iron ore for steelmaking; culturally famous as red ochre pigment. In the studio: cabochons, beads, intaglios, and sleek sculptural pieces that take a superb polish.
Care & Studio Notes 🧼💎
Everyday care
- Clean with lukewarm water + mild soap; soft cloth; dry promptly.
- Avoid harsh acids/bleach; earthy surfaces can dull and metallic polish can haze.
- Store away from harder gems (quartz/corundum) to prevent micro‑scratches on the mirror finish.
Jewelry guidance
- Great for beads, cabochons, signet‑style pieces. Its heft feels luxurious in hand.
- Pair with matte silver or blackened metals for modern contrast; warm gold softens the graphite look.
- For bracelets/rings, consider micro‑bevels on exposed edges to reduce visible scuffs.
On the wheel
- Pre‑polish thoroughly (600→1200→3k). Keep pressure light to avoid drag marks on metallic faces.
- Finish with alumina or diamond on leather; a whisper of microcrystalline wax can protect display pieces.
- For botryoidal pieces, accept a satiny finish—chasing mirror gloss across micro‑curves invites undercutting.
Hands‑On Demos 🔍
The streak test (smart & gentle)
Rub a tiny corner on an unglazed porcelain tile (or the back of a thrift‑store tile). Hematite writes a red‑brown line every time. Use a hidden spot or a small chip to keep display faces pristine.
Heft check
Compare equal‑size tumbled stones: hematite feels significantly heavier than quartz or jasper. Your palm will notice before your brain does.
Small joke: hematite is the friend who wears black to every party—but leaves a red autograph on the guest book.
Questions ❓
Will hematite make my skin black or rusty?
No. A polished hematite surface is stable. Any dark rub‑off is usually residue from handling/polishing compounds and wipes away.
Why isn’t my “hematite” bracelet magnetic?
That’s normal for natural hematite. Strongly magnetic beads are typically synthetic ferrites sold as “magnetic hematite.” Still pretty—just different.
Is specularite rarer?
It’s a habit, not a species. Good, mirror‑bright plates from certain localities are sought after, but all are hematite.
Can hematite be red as a gemstone?
As a solid, hematite is metallic grey/black; the red shows in powder. Red “hematite” cabochons are usually jaspers or iron‑rich quartzes.
Good for everyday wear?
Yes—with mindful storage. It’s reasonably hard but the mirror finish shows scratches more readily than a textured stone.