Cranberry Tourmaline Identification Guide

What Cranberry Tourmaline Looks Like

Cranberry tourmaline is a trade name for a deep, slightly purplish red-pink elbaite tourmaline, in the rubellite color range, colored mainly by manganese. The color is a rich cranberry-red to raspberry-pink, often with a cool purplish undertone. Luster is glassy (vitreous); transparency runs transparent to translucent. Crystals are trigonal, forming elongate prisms with the classic rounded-triangular cross-section and strong lengthwise striations down the prism faces. It often shows noticeable pleochroism (color shifts in different viewing directions). Faceted stones are bright and saturated; rough appears as striated prisms in pegmatite, sometimes with internal threads or inclusions.

Step-by-Step Field ID Checklist

1. Assess the color. Deep cranberry-red to purplish-pink is the signature.
2. Check crystal shape. Rounded triangular cross-section with prominent lengthwise striations indicates tourmaline.
3. Observe pleochroism. Rotate the stone; tourmaline shows different color depths along/across the crystal.
4. Confirm hardness (below).
5. Look for inclusions. Rubellite-type tourmaline often has fine internal fractures and threads.
6. Note origin clues. Brazil, Mozambique, Madagascar, Nigeria, and Afghanistan are common sources.

Key Diagnostic Tests

• Hardness: 7–7.5; scratches quartz and glass.
• Streak: White (colorless).
• Cleavage/fracture: Cleavage absent to very poor; conchoidal to uneven fracture.
• Magnetism: None.
• Acid: No reaction.
• Density: ~3.0–3.1 g/cm³.
• Optics: Strongly pleochroic and doubly refractive (uniaxial), which helps separate it from singly refractive look-alikes like garnet.

Common Look-Alikes and How to Tell Them Apart

• Rubellite (other pink-red tourmaline): Same mineral; "cranberry" simply denotes a deep purplish-red hue within the rubellite range, so the separation is one of color grade, not species.
• Pink/red garnet (rhodolite, almandine): Garnet is singly refractive (no pleochroism), often denser (3.6–4.3), and forms dodecahedral crystals, not striated prisms.
• Ruby/pink sapphire: Harder (9), corundum crystals, and much denser; tourmaline is 7–7.5.
• Pink topaz: Has a basal cleavage and different crystal form; tourmaline lacks easy cleavage and shows striated trigonal prisms.
• Pink glass/synthetics: Glass has bubbles and no pleochroism; synthetic rubellite needs gemological testing.

Where It Is Typically Found

Cranberry tourmaline forms in granitic pegmatites. Major sources of red-pink elbaite include Brazil (Minas Gerais), Mozambique, Madagascar, Nigeria, Afghanistan, and Pakistan, where it occurs as gem prisms in pegmatite pockets alongside other colored tourmalines.