Original created by the Matrix of Alchemy to defend her laboratories from thieves and spies, these defenses were pressed into service as impromptu weapons when the dragon attacked. After her fall, their secret was discovered by House Arakshan who went on to use them extensively to protect their holdings.
Appearing as long and sharp white-green crystals, cloudy on poorly-made ones, nearly invisibly colored in superb ones, they are hung from decorations, inset in walls and doors, but at least half of the crystal must be exposed for it to function. Stuck, they sound with a hissing whine rather than a chime and may fracture and burst in a spray of acidic fragments.
They are keyed to particular things, bloodlines, amulets, it varies, that will not trigger them. Those that do not possess those traits are attacked by razor sharp crystalline shards that dissolve into acid.
Acid Crystal Trap (CR 3) XP 800
Sea of Stars RPG Design Journal 