Imperial Rune Emerald

From the Latin imperialis, of the empire — applied to color since the medieval period for the hues reserved for sovereigns and empires: imperial purple of Tyrian dye, imperial yellow of Ming-dynasty porcelain. As a modifier, imperial implies saturation combined with the institutional weight of a color owned by a court. Sits in the bold-and-deep corner, alongside royal.

Old Norse rún, secret-or-runic-letter. As a color modifier, rune implies a Norse-runic-letter-and-Futhark-and-incised-stone quality, the visual register of Elder-Futhark-and-Norse-runic-stone hand-Norse-runic-letter-and-Futhark-and-incised-stone Elder-Futhark-and-Norse-runic-stone-and-Viking-grave-marker rune-and-Norse-runic-letter-and-Futhark surfaces under Elder-Futhark-and-Norse-runic-stone-and-Viking-grave-marker Jelling-stone-and-Rök-runestone runic-incision-light. Sits at the modifier-and-myth end of the grid, parallel to omen and sigil in usage.

A chromium-tinged variety of beryl — the gemstone mined from the Cleopatra-era Mons Smaragdus in Egypt, the Muzo deposits of Colombia, and the Sandawana mines of Zimbabwe. Emerald green refers to a high-clarity faceted emerald with strong color saturation: a saturated, slightly blue-shifted green with the gem's signature internal life. Cooler than fern, warmer than teal, with the heraldic weight of two thousand years of royal favor.