Fossil coral (珊瑚玉) is a natural type of gemstone formed by ancient corals. The proper name for fossil coral is 'agatized coral' or 'agatized fossil coral', because during formation, the coral remains are gradually replaced with agate, a variety of naturally occurring chalcedony, or microcrystalline quartz. When prehistoric corals are fossilized through replacement with agate, the fossil coral forms through hardened deposits left by silica-rich waters. The entire process can take over 20 million years and occurs only under very unique geological conditions. Corals are marine animals and it is their skeletons that are fossilized and preserved, often leaving flower-like patterns in the stone. Due of its unique beauty, colour alot of people transform it into jewellery. Every piece is a master piece and unable to find a similiar piece with same pattern or colours. Is like a work piece of art. In Taiwan, China and Europe country likesto keep as a collectable item due this gemstone unable to reproduce again and needs to wait for another 10 millions years. Since now is not so popular at most of the Asian country, don't wait start to collect one of your favourite piece. Or else after few years time you unable to get any. Happy collecting!