Magnesite and Dead-Burned Magnesia

What magnesite and Dead-Burned Magnesia actually is

Magnesite and Dead-Burned Magnesia is classified as magnesium carbonate rock calcined at very high temperature to dense periclase, the workhorse basic refractory for steelmaking, with the composition Magnesite MgCO3 calcined to periclase MgO, typically 90-98% MgO. It crystallises in the trigonal (magnesite); cubic (periclase) system.

Colour comes from white to buff; iron content darkens it and affects refractory performance, which is also what a laboratory looks at when it is asked whether a colour is natural.

Refractive index 1.509-1.717 (magnesite); 1.736 (periclase). Specific gravity around 2.98-3.02 magnesite; 3.4-3.6 dead-burned. Cleavage: perfect rhombohedral in magnesite. Those three numbers separate it from most of what imitates it.

Where magnesite and Dead-Burned Magnesia comes from

Magnesite and Dead-Burned Magnesia is produced at Haicheng and Dashiqiao, Liaoning Province, China - roughly two-thirds of world supply, Radenthein and Breitenau, Styria, Austria, Kumas and Eskisehir, Turkiye, Serra das Eguas, Brumado, Bahia, Brazil and Jelsava, Slovakia; Russia; North Korea.

The locality is part of the description, not a footnote — two stones of the same weight from two of these places are not the same stone.

How magnesite and Dead-Burned Magnesia is treated

Dead-burned at 1,600-2,000 C, or electrofused at above 2,800 C for the premium fused magnesia grades. Uses: basic refractory brick and gunning mixes for steel converters, electric arc furnaces and cement kilns; magnesia-carbon brick; insulation for tubular heating elements (fused magnesia); plus caustic-calcined magnesia for agriculture, animal feed, environmental treatment and magnesium oxychloride cement. SUPPLY CONCENTRATION: Chinese production dominance and periodic environmental shutdowns in Liaoning have caused severe global price spikes, and magnesite is on the EU critical raw materials list for that reason.

Treatment changes value, sometimes by a multiple, so it belongs in the description before the price and not after the sale.

What magnesite and Dead-Burned Magnesia is confused with

In the trade magnesite and Dead-Burned Magnesia is most often mistaken for, or substituted by, Dolomite refractories (the cheaper basic alternative), Alumina and chrome refractories or Synthetic magnesia from seawater and brine (a significant alternative feedstock).

The separation is rarely a matter of opinion: refractive index 1.509-1.717 (magnesite); 1.736 (periclase) and specific gravity 2.98-3.02 magnesite; 3.4-3.6 dead-burned settle most of it in a minute, and magnification settles the rest.

What magnesite and Dead-Burned Magnesia is used for

Demand for magnesite and Dead-Burned Magnesia comes from heavy industry and kitchen and table, which is why one price per carat never covers it.

We quote each application in the unit that trade actually buys in, by the tonne or by the piece.

Durability and care

Hardness 3.5-4.5 (magnesite); periclase 5.5-6; cleavage perfect rhombohedral in magnesite. That combination decides what it can safely be set into.

Below about 5.5 a stone will be scratched by ordinary household dust, which is largely quartz. That does not make it unusable — it makes it a pendant, an earring or an object rather than a ring worn every day.

Warm water, mild soap and a soft brush. Avoid ultrasonic cleaners on anything fracture-filled, stabilised, dyed or visibly included.

What magnesite and Dead-Burned Magnesia costs

As a guide, magnesite and Dead-Burned Magnesia trades around $400-900 per tonne for dead-burned magnesia; fused magnesia $700-1,600 per tonne, with sharp cyclical swings.

That is a range, not a quote. Colour, size, clarity, cut and origin move the figure a long way inside it, and the only honest price is one given against a specific stone. Send us what you need and we will price it.

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