Quartz + rutile, a photogenic duo

The host is quartz—transparent to smoky, sometimes slightly milky. The inclusions are rutile (TiO₂), a high‑RI, high‑dispersion mineral that loves to grow as acicular (needle‑like) crystals. Together they create a 3D drawing inside a crystal.

Sagenitic vs. rutilated

Rutilated quartz specifies the inclusion species. Sagenitic quartz describes the look—a net of needles—and could be rutile, goethite, or others. When you can, label by the mineral you see.

Capture during growth

Rutile needles form first in a cavity or along tiny substrates. Later, silica‑rich fluids deposit quartz that overgrows the rutile, sealing the needles inside like insects in amber—only shinier.

Epitaxy & alignment

Rutile and quartz can share crystallographic relationships, so needles often align with the quartz c‑axis or intersect one another at neat 60°/120° angles. The result: orderly bundles, fans, and tidy cross‑hatches.

Hematite “stars”

Thin hematite plates sometimes act as a seed. Rutile radiates from the plate edges, producing dramatic starbursts—a favorite from certain Brazilian localities.

Color of the needles

Rutile is naturally golden to reddish‑brown (trace iron + internal scattering). Weathered surfaces can pick up oxide films that warm the color toward copper.

Host varieties

Most examples are in rock crystal, but needles occur in smoky, amethyst, and even citrine. Dark hosts make gold needles blaze; pale hosts showcase the geometry.

Not exsolution

Unlike some “exsolution” textures in feldspars, the rutile wasn’t squeezed out of quartz—it was present first and got encapsulated as quartz grew.

Palette

• Gold — classic, mirror‑bright rutile.
• Copper/bronze — thicker needles or oxide‑warmed surfaces.
• Smoky host — needles glow like backlit filaments.
• Amethyst host — violet glass with golden threads (chef’s kiss).
• Hematite accents — red plates at the hub of radiating sprays.

Needles range from hair‑fine to bold “darts.” The best pieces balance clarity with density—enough threads to tell a story, enough window to see it.

Pattern words

• Parallel “hair” — aligned along the crystal length.
• Cross‑hatch — 60°/120° intersections creating lattices.
• Fans & sprays — needles radiating from a point.
• Starburst — rutile rays from a central hematite plate.
• Sagenitic net — dense, chaotic webs (dramatic but still elegant).

Photo tip: One small light at ~30° and a dark card behind the stone. Move the stone, not the light—the needles will flare on cue.

Rutile tells

Needles are metallic‑bright, often perfectly straight, with sharp tips. Intersections at tidy 60°/120° are common; dense bundles may show faint striations along length.

Hematite hubs

Look for thin, red‑bronze plates that act as hubs with rutile rays shooting out. The plate is opaque; the rays glint as you tilt.

Surface vs. interior

True inclusions show parallax: they appear to move against the background as you tilt. Surface stains or coatings don’t—plus, a toothpick can dislodge a coating (don’t try on display faces).

Tourmalinated quartz

Tourmaline rods are thicker, jet‑black, and strongly striated; they rarely show golden metallic shine. Cross‑sections can look triangular/rounded, not needle‑fine.

Actinolite “green hair”

Silky, green fibers with lower luster; often slightly curved. Rutile stays straight and mirror‑bright in gold/bronze tones.

Goethite/lepidocrocite

Orange‑rust platelets or soft needles with glittery but non‑metallic sheen; often appear as “confetti” rather than crisp wires.

Dyed crackle quartz

Color pools along fractures; under 10× you’ll see branching cracks filled with uniform dye—not discrete crystals with geometry.

Glass with copper glitter

Man‑made “goldstone” sparkles evenly and lacks needle morphology. Quartz + rutile shows distinct, three‑dimensional crystals.

Quick checklist

• Metallic gold/bronze needles? ✓
• Neat 60°/120° crosses or parallel bundles? ✓
• Depth & parallax as you tilt? ✓

Brazil

Bahia & Minas Gerais are renowned—think radiating starbursts from hematite hubs and dense golden hair in water‑clear rock crystal.

Madagascar & the Himalaya

Madagascar produces airy, well‑spaced needles that photograph beautifully. Pakistan/Afghanistan pieces often pair rutile with Alpine‑level clarity and elegant parallel bundles.

Elsewhere

Fine examples also appear from India, the Alps, and sporadically worldwide—anywhere quartz veins had the right titania‑rich chemistry at the right time.

Everyday care

• Quartz is hard, but points and edges can chip—handle like a fine camera lens.
• Clean with lukewarm water + mild soap + soft brush; rinse & dry.
• Avoid thermal shock and aggressive ultrasonics on heavily included stones.

Display

• Use side‑light around 30° and a dark backdrop to ignite the needles.
• Rotate pieces periodically—different angles “light” different threads.
• Store away from softer gems (quartz tends to win scratch‑offs).

Lapidary

• Orient domes so bundles traverse the apex (maximum drama).
• Take a patient pre‑polish (to 3k–8k) → finish with cerium/oxide on a soft pad.
• If needles break surface, expect slight undercut; light pressure and fresh belts help keep the polish even.

Find the star

With a 10× loupe, hunt for a tiny red‑bronze plate. If you spot one, trace the rutile rays outward—you’ve found a hematite‑seeded starburst.

Angle magic

Hold a penlight fixed and rotate the stone. Watch different bundles flare then fade as they catch the light—like turning constellations on and off.