- any of a group of minerals composed principally of oxides of magnesium, aluminum, iron, manganese, chromium, etc., characterized by their hardness and octahedral crystals.
- a mineral of this group, essentially magnesium aluminate, MgAl2O4, some varieties being used as gems.
Origin of spinel
1520–30; < French spinelle < Italian spinella, equivalent to spin(a) thorn (< Latin spīna) + -ella -elle
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
Examples from the Web for spinel
The hardness of Spinel is 8, or about that of topaz, and the specific gravity 3.6.
A ring with a spinel ruby in it dropped out: she recognised the stone—it was Miss Minerva's ring.Heart and Science
The natives of India call the Spinel the pomegranate ruby and believe to this day that it possesses valuable medicinal properties.
Spinel is singly refracting in polarized light and corundum doubly refracting.
Not only is Spinel ruby related to corundum ruby in color and use, but the two are frequently associated together in nature.
- any of a group of hard glassy minerals of variable colour consisting of oxides of aluminium, magnesium, chromium, iron, zinc, or manganese and occurring in the form of octahedral crystals: used as gemstones
- a hard, glassy mineral composed of magnesium-aluminium oxide found in metamorphosed limestones and many basic and ultrabasic igneous rocks. Formula: MgAl 2 O 4
C16: from French spinelle, from Italian spinella, diminutive of spina a thorn, from Latin; so called from the shape of the crystals
- A hard, variously colored cubic mineral, having usually octahedral crystals and occurring in igneous and metamorphosed carbonate rocks. The red variety is valued as a gem and is sometimes confused with the ruby. Chemical formula: MgAl2O4.
- Any of a group of minerals that are oxides of magnesium, iron, zinc, manganese, or aluminum.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.