Bloodworms are the only organisms that are known to produce copper biominerals. Most living things produce calcium-based minerals.
Each one contains a small amount of the copper-based mineral atacamite. The highest concentrations of atacamite are found near the tip.
The jaws are hard and wear resistant despite the low concentration of mineral. Human teeth have a mineral to protein ratio that is approximately ten times higher than in bloodworm jaws. Copper is toxic to most living things.
Copper in non-mineral form also exists in the bloodworm jaws.
The wear resistance of bloodworm jaws is comparable to that of dentin, but slightly less than that of enamel.
Some, but not all of them contain a narrow venom channel.
Like spider silk and mussel byssus, these may be an inspiration for the design of biomimetic materials.