Rubellite Identification Guide

What Rubellite Looks Like

Rubellite is the trade name for red to deep pink-red gem tourmaline (lithium-rich elbaite). The defining trait is that the saturated red color holds under both daylight and incandescent light, unlike lesser pink tourmalines that go brownish.

• Color: Ruby-red, raspberry, magenta to deep pink.
• Luster: Vitreous.
• Transparency: Transparent to translucent.
• Habit: Long prismatic crystals with rounded triangular cross-sections and strong vertical striations.
• Pleochroism: Distinct — color tone shifts when viewed down versus across the crystal.

Step-by-Step Field-ID Checklist

1. Check the cross-section. A rounded triangle (trigonal) is diagnostic of tourmaline; ruby and garnet are not prismatic in this way.
2. Feel the striations. Deep parallel grooves run along the prism length.
3. Rotate for pleochroism. Rubellite visibly changes tone as you turn it.
4. Test hardness — scratches glass cleanly (Mohs 7-7.5).
5. Test color stability — true rubellite stays red in both daylight and warm indoor light.

Key Diagnostic Tests

• Mohs hardness: 7-7.5.
• Streak: White.
• Cleavage: Indistinct; conchoidal/uneven fracture.
• Density: ~3.06 g/cm3.
• Pyro/piezoelectricity: Warms to attract dust — a tourmaline hallmark.
• Inclusions: Often has thread-like tubes and fluid inclusions, contributing to a slightly included look compared to ruby.

Common Look-Alikes and How to Tell Them Apart

• Ruby: Much harder (Mohs 9), denser (~4.0), and forms tabular/barrel hexagonal crystals; ruby shows red fluorescence under UV, rubellite generally does not.
• Red garnet (almandine/pyrope): Isotropic (no pleochroism), equant dodecahedral crystals, denser; rubellite is doubly refractive and prismatic.
• Red spinel: Octahedral crystals, isotropic, no striations.
• Pink tourmaline/rose tourmaline: Same species, just lighter and less saturated than rubellite.
• Pink topaz: Has perfect cleavage and higher density.

Where It Is Found

Rubellite occurs in lithium-rich granite pegmatites. Major sources include Brazil, Madagascar, Nigeria, Mozambique, Afghanistan, and California (USA).

Field Tips and Common Mistakes

The defining commercial test for rubellite versus ordinary pink tourmaline is the lighting check: place the stone first in daylight, then under warm incandescent light. True rubellite holds its red or vivid pink in both, while lesser stones visibly turn brownish or grayish under tungsten light. This simple comparison, combined with the diagnostic triangular cross-section and prism striations, separates rubellite from look-alikes without any instruments.

A common error is paying ruby prices for rubellite or vice versa. Remember ruby is corundum at Mohs 9 and noticeably denser, often with red UV fluorescence; rubellite is tourmaline at Mohs 7-7.5 with strong pleochroism and frequent fluid-filled tube inclusions that give it a slightly "wispy" interior. Heavily included rubellite is normal and not a sign of fakery, but glass imitations betray themselves with rounded bubbles and a lack of pleochroism.