Reposeful Arch Topaz

Latin repōnere, to put back — adjectival suffix -ful. As a color modifier, reposeful implies a clear-and-restful-and-still quality, the calm color of pre-modern monastic cloister-and-refectory meditative-and-silent interior architecture. Sits at the crisp-and-calm end of the grid, parallel to peaceful and placid in usage.

Latin arcus, bow / curve. As a color modifier, arch implies a Roman-and-Gothic-and-Romanesque-vault quality, the visual register of Roman-aqueduct-and-Romanesque-cathedral hand-cut stone-and-brick voussoir-and-keystone arch-and-vault architectural surfaces under monumental architecture light. Sits at the modifier-and-architecture end of the grid, parallel to dome and vault in usage.

A fluorine aluminum silicate gem, hardness 8 on the Mohs scale, mined for centuries in Ouro Preto, Brazil. Imperial topaz is the prized variety: a warm, slightly pink-shifted gold-orange with the high refractive index of a quality cut stone. Cooler than amber, brighter than honey, with the gem's signature internal fire when held to light. Named for the island of Topazos in the Red Sea, though that source produced peridot instead.