The rock is mainly formed by the sedimentation of calcium and limestone from an ancient seafloor, but there are 3 distinct types of rock that we come across.
The first type of rock we quarry is formed from ancient corals, tube worms and other forms of sea life. Buried in time by calcium carbonate sediment, shells and the skeletons from coralline algae this rock is eventually bonded with lime and buried deep within the earth. After it is returned to the surface, it is extensively cleaned to bring out the raw natural form. The genuine article, in some cases fossilized tube worm shells and other skeletal remains are still present, somehow managing to withstand the pressure of millions of years of wave lapping erosion and 3 days of carrier handling.
The second type of rock we find is made from the process of water seeping through the sediment lime rock, (aragonite based rock). Water found deep in the earth is devoid of oxygen and therefore has a low ph. Much like how a calcium reactor breaks down aragonite chips to release calcium, the low ph water deep within the earth has bored holes into this rock, adding the to the features that would otherwise be missing from just natural sea floor based rock. Each drip over the millions of years it was buried have formed structures for your fish and corals to call home that is unparalleled.
The final type of rock we come across has similar looking holes and structures as our rock, but has been formed by the release of gas pockets created by the decay of living organisms. This rock needs extensive curing to make it aquarium safe, and even then it still has a tendency to leach phosphates over time. Our staff is trained to recognize these rocks, remove them from the quarry and keep them separate at all times from the rock that is destined for our customers.