Hard, bright, rarely treated and found in almost every colour. Here is what to know before you choose one.
What spinel is
Spinel is a magnesium aluminium oxide that crystallises as sharp octahedra, the shape in our logo. It scores 8 on the Mohs hardness scale, so it is tough enough for rings worn every day. It is singly refractive, which gives it a clean, crisp sparkle without the doubling you see in some gems.
For centuries, red spinel was simply called ruby. Some of the most famous “rubies” in royal regalia, including the Black Prince’s Ruby in the British Imperial State Crown, are spinels. Spinel was recognised as its own mineral in the late 18th century, and in 2016 it was added as a birthstone for August.
Colours
Spinel’s colour comes from trace elements: chromium for reds and pinks, iron for violets, lavenders and greys, and cobalt for the rare vivid blues.
Red
Coloured by chromium. The classic Burmese colour and the one long confused with ruby.
Neon pink
Chromium again, in a lighter body tone. Mahenge stones can look almost fluorescent in daylight.
Cobalt blue
The rarest blue: coloured by cobalt rather than iron. Found mostly in small sizes.
Lavender and violet
Iron-coloured, often from Burma and Sri Lanka. Good value for large, clean stones.
Grey
Steel and silver greys, bright and modern. Usually very affordable per carat.
Orange
Uncommon. Ranges from flame to a soft peach.
Where it comes from
Myanmar (Burma)
Mogok and nearby Namya are the classic sources of fine red, pink and lavender spinel. Burmese stones are often small but richly coloured.
Tanzania
Around Mahenge, a major find in 2007 produced large crystals of intense neon pink and red. Mahenge is now one of the most sought-after origins.
Vietnam
The Luc Yen district produces pinks, purples and the rare cobalt blues, usually in small sizes.
Sri Lanka
Ceylon spinels tend toward violet, lavender, blue and grey, and often come in larger, clean sizes.
Tajikistan
The historic mines of Badakhshan supplied the “balas rubies” of medieval treasuries. Production today is limited.
Treatment
One reason collectors love spinel: it is almost never treated. Heating rarely improves its colour, so the stone you buy is usually exactly as it came from the ground. We list the treatment for every stone. If a stone has a lab report, we name the laboratory; for others, a report can be arranged on request.
What affects price
Colour first. Vivid, saturated reds, neon pinks and cobalt blues command the highest prices per carat.
Size. Fine spinel over 2 carats is uncommon, and price per carat rises sharply with size.
Clarity. Most fine spinel is eye clean. Small inclusions you can only see under magnification affect price far less than colour.
Cut. A well-cut stone shows colour across the whole face with no dark or washed-out windows.
Origin. Burmese and Mahenge stones often sell at a premium, though colour matters more than the name on the paper.
Caring for spinel
Clean spinel with warm water, a drop of mild soap and a soft brush. It is stable in light and resists most household chemicals. Store it apart from diamonds and sapphires, which are harder and can scratch it.