Fossil coral occurs throughout the world. Reefal limestone are in essence fossil remnants of coral reefs. Massive preservation of coral reefs has occurred for hundreds of millions of years. Agatised fossil corals are known to occurs in many parts of the world, Thailand, china, USA, Indonesia and dozens of other countries.

But it is rare that the silicification process takes place and preserves the coral polyp image. The agatised coral is collected along stream beds or by digging pits in the mountains where exposures of the Miocene lime stones outcrop.

We slab off agatised top end of the coral where the best polyp images are preserved. This was the most porous portion and therefore received the most exposure to element in the groundwater. The usable (polish able) material less than 5% of the rough. Another 70% is waste from the cutting and polishing. Polish able material with preserved clear defined coral polyp images is a mere fraction of the polish able material. Perfect images are relatively rare. Colors vary widely depending on the extent of exposure to iron and other elements in the reacting groundwater solutions.