Spelunker Glowstick

Spelunker Glowsticks work like Glowsticks, which can be held or thrown to illuminate an area, even under water; however, Spelunker Glowsticks additionally highlight nearby treasure with a yellowish glimmer. Spelunker Glowsticks are sold by the Skeleton Merchant.

Tips

 * These glowsticks will display nearby treasures while simply being held, meaning you do not have to throw one for the effect to take place. This creates a use for having a spelunker glowstick on the hotbar while mining: every 30 seconds or so, switch to the spelunker glowstick (do not throw it), and you will be able to see nearby ores as long as you have it selected, which is very helpful in the early game. This technique can later be replaced by equipping a Magic Lantern.
 * The spelunker glowsticks actually have a bigger radius than the Magic Lantern in which they spot treasures.
 * When the spelunker glowsticks' time expires, unlike the original glowstick, it'll just disappear, rendering it unreusable.
 * Other players can see the particles created by the user with the glowsticks, which makes it helpful to have on a mining trip with friends.
 * The yellow glimmer emitted from nearby treasures will not actually show or indicate the type of treasure, rendering it somewhat useless in the end game due to early game ores being highlighted with the same exact shine as valuable ores.
 * Spelunker glowsticks will not indicate hard-mode ores.

Trivia

 * The Spelunker glowstick seems to have been made out of a bone.

History
Bâton Lumineux de Spéléologue