Obsidian Athens Ultramarine

Volcanic glass — molten rhyolite cooled too quickly to crystallize. Mined since the Stone Age for blade-edges (sharper than surgical steel) and ground into mirrors by the Aztec priesthood for divination. The color refers to a polished obsidian flake from Mount Hekla or Glass Buttes, Oregon: a deep, slightly blue-shifted black with the high-gloss conchoidal fracture of natural glass. Cooler than onyx, glossier than coal.

Greek Ἀθῆναι, Athens. As a color modifier, athens implies an Acropolis-and-philosophical-city-state quality, the visual register of Athenian-Classical-City-State hand-built Acropolis-and-Parthenon-and-marble-temple-and-pottery Doric-and-Ionic-and-Corinthian surfaces under Athenian-Acropolis-and-Parthenon classical Aegean-marble-temple light. Sits at the modifier-and-cultural end of the grid, parallel to sparta and greek in usage.

The pigment ground from lapis lazuli — the Afghan mineral imported through Venice in the late Middle Ages, more expensive by weight than gold during the Renaissance. The color refers to a freshly mixed ultramarine pigment in linseed oil: a saturated, slightly violet-shifted deep blue with the matte finish of micron-ground rock. Deeper than cobalt, cooler than royal, with the art-historical weight of the blue Vermeer reserved for Mary's robe.