Spinel

Spinel is magnesium aluminate that comes in every color — red, pink, orange, blue, violet, black. For most of history it was mistaken for ruby and sapphire. The largest “ruby” in the British Crown Jewels (the Black Prince’s Ruby) is in fact a 170-carat red spinel; the Timur Ruby is another. Only in 1783 did chemists separate spinel from corundum as distinct minerals.

Mohs 8 puts it comfortably in daily-wear territory. And unlike ruby and sapphire, spinel is almost never heat-treated — the natural color is the color you keep. That makes it a connoisseur’s pick.

Color

Why spinel is a smart buy

The trade case for spinel:

1. Almost always untreated. Spinel doesn’t respond to heat treatment the way corundum does, so the stones come out of the ground at their final color. No oil, no irradiation, nothing to disclose.
2. Hard enough for daily wear. Mohs 8 with no cleavage planes.
3. Genuinely rare. Fine red and cobalt-blue spinel deposits are small. Less supply than sapphire or ruby in similar grades.
4. Significantly cheaper than equivalent ruby/sapphire. A fine-color red spinel costs 30–60 % of comparable Burmese ruby.

The downside: name recognition. Most customers don’t know “spinel” — which is exactly why it’s priced as it is.

Origin

• Burma (Mogok) — produces the most prized red spinel. The spiritual home of the variety.
• Tanzania (Mahenge) — discovered in 2007. Produces uniquely vivid pink-red stones; a recent darling of the trade.
• Sri Lanka (Ceylon) — wide color range; cleaner crystals than Burmese.
• Tajikistan (Pamir) — historical source of cobalt-blue spinel.
• Vietnam (Luc Yen) — cobalt-blue and pink production.