Spinel Material Properties

Spinel, or magnesium aluminate spinel, is a durable cubic single crystal material. Its desirable and unique qualities include: durability, chemical resistance, high hardness, high strength, and good shock resistance.

The material looks the same as glass but has properties 3x harder, 6x stronger and with 10x the abrasion resistance of glass. Due to its excellent mechanical properties, spinel survives in far higher temperatures and more aggressive chemical environments than glass. Due to its monocubic structure, spinel has almost no refringence.

With optical transparency ranging from the near ultraviolet through the mid-wave infrared spectrum, spinel is transparent in spectral ranges where glass is as opaque as steel. Spinel is a very interesting material for optical applications.

Applications: Precision optical components, ball lens for optical telecom products.

Spinel (typical values)

Crystalline Structure Cubic monocrystal
Composition MgAl2O4
Purity 99.99%
Density 3.61 g/cm3
Dislocation Density 109 – 108 /m2
Melting Point 2300 – 2330 K
Softening Point 2070 K
Specific Heat 7.9 x 102 j/kg x K at 300 K
Thermal Expansion 5.9 x 10-6 /K
Hardness Mohs 8 Knoop 1175 – 1380
Young’s Modulus 4.4 x 1011 Pa at 300 K
Modulus of Rupture 4.0 x 108 Pa at 300 K
Compressive Strength 2.1 x 109 Pa at 300 K
Tensile Strength 1.9 x 108 Pa at 300 K
Poisson’s Constant 0.30
Dielectric Constant 8 – 9
Refractive Index ND at 0.5893 µm 1.727
Infrared 85% 1µm