Rhyolite beads (Madagascar jasper).
This unusual breed was found in a native occurrence along the northwestern coast of Rhyolite beads. The deposit is a rhyolite stream that has been completely silified. Rhyolite beads is mined only in one mine near Maruvatu (Marovato). The deposit, since it is located on the edge of the ocean, can only be developed at low tide. There are no roads in this remote part of the island, so the extracted material (Madagascar agates and jaspers) it is exported by boats.