Definition of spinel in US English:



  • 1A hard glassy mineral occurring as octahedral crystals of variable color and consisting chiefly of magnesium and aluminum oxides.

    • ‘Dark pink and crimson-red colors are added to the display by the presence of spinels and pyropealmandine garnets.’
    • ‘Rubies were found in Burma and Ceylon, topaz, beryl, garnet, amethyst and pearl in Ceylon and Southern India, and spinels and deep blue sapphires in Afghanistan and Kashmir.’
    • ‘His collection includes emeralds and spinels of a staggering size (some of them are nearly 300 carats).’
    • ‘Legendary for its blood-red rubies and spinels, the Mogok stone tract of northern Myanmar also produces an amazing array of other minerals.’
    • ‘Even the famous Black Prince Ruby in the British Imperial State Crown is actually a spinel, not a ruby.’
    1. 1.1Chemistry Any of a class of oxides including this, containing aluminum and another metal and having the general formula MAl₂O₄.
      • ‘We've put meat behind the idea that provided the theoretical basis for understanding the specific compositions of the spinels in terms of the model that they are condensates from the vapor.’
      • ‘UCLA's Kyte, who himself favored a fireball origin for the spinels, has measured the chemical composition of hundreds of spinel samples from around the world.’
      • ‘Examples of coexisting spinels in chemical equilibrium are uncommon at Hutter.’
      • ‘The spinels have low Mg number in comparison with Alpine-type peridotites, suggesting hydrothermal alteration in which Cr is preferentially retained in spinel.’
      • ‘At both Bald Knob and Hutter, rhodonite is absent in samples containing manganese spinels or manganese humites.’


Early 16th century: from French spinelle, from Italian spinella, diminutive of spina ‘thorn’.