Starlight Shards are among the rarest and most valuable consumables in Elden Ring, especially for players who lean heavily on magic. Unlike Cerulean Tears, which instantly refill your Focus Points (FP), Starlight Shards grant a slow and steady FP regeneration effect over time. This makes them ideal for long exploration sessions, drawn-out boss fights, or when you're conserving Flask charges in difficult areas. However, because there are only a limited number of them in each playthrough, understanding where to find them and how to use them effectively can give you a significant edge.
https://www.mmoexp.com/Elden-ring/Runes.html