Since the year 2000 “Ocean-Jasper” is the “piece de resistance” from Madagaskar. It occurs on the Analava peninsula near to the town Mahajunga. It is very difficult to reach the gem-bearing shore from the landside. The miners are trying to reach the mining area from the seaside at low tide (“Ocean-Jasper”).
Former theories are describing this multicoloured spherulitical Jasper as an silificied rhyolitic vulcanic rock. W. Lieber (2003) is categorizing this material as an spherulitical chalcedony.
This jasper does show a pattern remaining at “eye-agates”. The eyes are spheres of concentrical banded chalcedony. These spheres are hovering in a fine grained mass of chalcedony. This chalcedony may have an greenish appearance - but the material can be as well coloured in any tone of the rainbow.
The spherulithics of one formation often are having the same size and same structure. Sometimes star-quartz is formed by phanerocristallinic quartz pointing on a chalcedony-sphere. Some parts of the deposit may have been changed in structure by metamorphical conditions. This was developing a floating structure and fading of colours in the rock.
The mine was last productive in the year 2008 and is runned out now.
More informations about this material and the locality is given from Prof. Dr. Werner Lieber in his article “Sphärolitischer Chalcedon von Madagaskar” in Lapis 28 (9), page 18 - 22 (2003) and from Johannn Zenz in his Agate-Monography (Bode Verlag 2005) on the pages 640 - 643.