.    First discovered on the Orellanita Ranch, they are better known as Crater Agate (or Red Fox Agate) which refers to the fact that the agates are said to be found close to an ancient crater of volcano. It was insisted that they be called "Orellanita Agates" after the owner of the land where those agates are found and they had been marketed under different names. The typical colors are black, dark gray and dark yellow, and I have seen a few ones with blue color (rare?). Most agates are hollow, and tend to be coated with heulandite and other zeolite minerals. The hollow interiors of some black agates are coated with bright red hematite making them desirable, and like many agates from Argentina, it's expected to find many agates with fractures and higher price tags.

Rough Appreance: Usually cauliflower-shaped with very rough/pricky surface. Some are smoothier surface due to weathering.