Engravings, Etchings and Embellishments

"..and its surface is covered with engraving. It looks like.."

1. The flowing script of an archaic language. If interpreted, it details part of the history of an ancient society, including clues to their lost city.
2. Circles and arcs of varying size and width, with ornate symbols. A wizard or astrologer will recognize it as alignments of planets, stars and planes.
3. Arcane sigils and glyphs, which form a still-potent magical ward.
4. The chiseled runes of dwarven master craftsmen. If interpreted, it contains metallurgy hints.
5. Intertwining vines and leaves.
6. Symbols, twisting script and repulsive depictions of evil rituals.
7. The symbol and heraldry of a Great Kingdom, the rule of which once included this area.
8. Repeating geometric patterns.
9. Weird shapes & pentacles, and strange symbols & script, arranged in patterns which a mage or cleric can tell was intended to contain an otherworldly entity.
10. Intertwining serpents.
11. Arabesque patterns of lines and ornate curves.
12. Circles and triangles of glyphs, narrow angular lines and patterns of tiny circles, all glowing with a dim light. If the surface is broken, the engravings continue to occupy the same points in space as before.
13. The story of the ascension of a deity, depicted in intertwining consecutive images.
14. Faces. Unless you look directly at it - then it just looks like chaotic lines and shapes.
15. The hieroglyphs of an ancient empire which covered the lands all around. Those who are able may read of their society, and perhaps be forewarned of an ancient curse.
16. The text of a recent religious tract, but illustrated with forbidden rites.
17. Stylized flowers, acorns, leaves and pine cones.
18. Lines of crude atavistic pictographs. Given time and perspicacity, anyone might glean their meaning.
19. Warriors and athletes of an ancient civilization.
20. Nightmare depictions of Elder Gods and ungulate horrors from the black gulfs of chaos. Save versus insanity.