Glowing crystals store some number of spellpoints and then return them to the character when needed by applying them just like any other item.

When a character has full spellpoints, applying the glowing crystal results in half of that characters maximum spellpoints being transferred to the crystal, up to the maximum amount the crystal can store (the default is approximately 500, but various crystals could have fewer while some could have more). If a player is below full spellpoints and applies it, instead the character draw points out of the crystal and into their SP up to their maximum spellpoints or when the crystal runs out of stored points.

The speed of the animation is a rough indicator of how charged the crystal is - the faster the animation, the more points it has.