Robust Horn Sapphire

From the Latin robustus, of oak — implying strength combined with substance. As a color modifier, robust describes saturation combined with body: a robust burgundy, a robust olive. Sits in the bold-and-warm corner alongside strong and solid, with the slightly textural implication of a color that has substance behind the pigment.

Old English horn, horn. As a color modifier, horn implies a translucent-keratin quality, the visual register of cattle-horn-and-deer-antler hand-shaped-and-polished translucent-keratin button-and-comb-and-knife-handle horn-and-antler surfaces under translucent-horn-and-antler hand-polished light. Sits at the modifier-and-texture end of the grid, parallel to bone and pith in usage.

An iron-and-titanium-bearing corundum — the same mineral as ruby, hardness 9 on the Mohs scale, mined for two millennia from Sri Lanka, Burma, Madagascar, and the Cashmere mines of British India. The color refers to a fine Kashmir-cut sapphire: a saturated, slightly violet-shifted deep blue with the gem's signature internal velvet — a quality of light scattering in the stone that faceted glass cannot replicate. Cooler than cobalt, deeper than azure.