Bekily Garnet Identification Guide

What Bekily Garnet Looks Like

Bekily garnet is a color-change garnet from the Bekily region of southern Madagascar, prized as one of the strongest color-change gems known. Chemically it is typically a pyrope-spessartine blend. Appearance:

• Color in daylight/fluorescent light: blue-green, teal, grayish-green, or bronze-green.
• Color in incandescent light/candlelight: purple, magenta, reddish-purple, or pink.
• Luster: bright vitreous, often near-adamantine when faceted.
• Transparency: transparent to translucent.
• Habit: rounded waterworn pebbles, anhedral grains, or rhombic dodecahedral crystals.

Field-ID Checklist

1. Confirm a garnet look: glassy, single-crystal, isotropic stone with no cleavage.
2. Move it between daylight and a warm (incandescent) bulb and watch for a strong color shift.
3. Note the green/teal-to-purple swing (vanadium/chromium driven) rather than a blue-to-red sapphire-style change.
4. Test hardness against quartz and topaz.
5. Check for the absence of cleavage and the presence of conchoidal fracture.

Key Diagnostic Tests

• Mohs hardness: 7–7.5, typical of garnet; scratches quartz, scratched by topaz.
• Streak: white.
• Cleavage: none — garnets fracture conchoidally to uneven, an important separator from many gems.
• Density: high, roughly 3.8–4.2 g/cm³; the stone feels heavy for its size.
• Optics: singly refractive (isotropic) — no doubling of back facets, distinguishing it from doubly refractive look-alikes.
• Color change: the defining test — a marked, repeatable shift under different light sources.
• Not magnetic to a hand magnet in most cases, though some garnets show slight attraction on sensitive setups.

Common Look-Alikes and How to Tell Them Apart

• Color-change sapphire: also shifts color but is harder (9), doubly refractive, and usually changes blue-to-purple; sapphire's greater hardness and birefringence separate it.
• Alexandrite (chrysoberyl): the classic color-change gem, harder (8.5), doubly refractive, and typically green-to-red; alexandrite shows pleochroism that garnet lacks.
• Color-change synthetic spinel/corundum: common in cheap jewelry; these are man-made, often with a vivid, almost neon shift and gas bubbles under magnification.
• Other garnets (rhodolite, malaia): related and sometimes overlapping, but lack the strong color change; the dramatic teal-to-purple swing flags Bekily material.
• Iolite: strongly pleochroic blue-violet but much softer-looking, lower density, and doubly refractive.

The combination of strong, repeatable color change, garnet hardness (7–7.5), high density, single refraction, and no cleavage points to Bekily garnet; gem-lab refractive-index and spectral testing confirms it.

Where It Is Found

The namesake source is the Bekily area of southern Madagascar, which produces the finest, most dramatic color-change garnets. Comparable color-change garnets also come from Tanzania (Tunduru, Songea), Sri Lanka, and Kenya, but "Bekily" specifically designates the Madagascar material.