'A nail,' as in Zechariah 10:4, signifies supporting truth.

(Verweise: Apocalypse Explained 355)

In Exodus 28:17, this signifies the celestial love of good. (Arcana Coelestia 9862) 'Lazuli, agate, and amethyst' denote the spiritual love of good. 'Beryl, onyx, and jasper' denote spiritual love of truth and 'sardine' signifies divine truth. 'Ruby, topaz, and carbuncle' signify the celestial love of good because of their red, flaming color. 'A covering of precious stones,' as in Ezekiel 28:13, signifies the truths of intelligence. 'Precious stones,' in application to the Word, symbolize the Divine truth of the Word in its literal sense which the Divine truth in its spiritual sense shines through. 'Chrysoprasus, sapphire, and diamond' denote celestial love of truth. 'Emerald' signifies the sphere of divine love and wisdom.

(Verweise: Apocalypse Revealed 911)