Amos 8:10

¹⁰ And I will turn your feasts into mourning, and all your songs into lamentation; and I will bring up sackcloth upon all loins, and baldness upon every head; and I will make it as the mourning of an only son, and the end of it as a bitter day.

Works, emeralds, purple broidered work, fine linen, coral, and agate

In Ezekiel 27:16, coral signifies knowledge of good. (Arcana Coelestia 1232)

Works, emeralds, purple broidered work, fine linen, coral, and agate, (Ezekiel 27:16), signify knowledges of good.

¹⁰ and if you draw out your soul to the hungry, and satisfy the afflicted soul: then your light shall rise in darkness, and your obscurity be as the noonday;