Technical Name - Ocos; Ochos
Location - Serra Geral Formation, Rio Grande do Sul, Brazil
Geological Age - 127-138 million years ago
What is a Geode?Imagine picking up a very plain dull looking rock, it seems solid but strangely light weight. Crack open this rock and what greets your eyes is a hollow centre full of glistening gems, this is a Geode. Hollow rocks like this are various sizes; typically between 25mm and 30mm across, either oval like a rugby ball or maybe a squashed shaped shape like a pasty.
They are most often of volcanic origin, having the classic crystalline centres of all the Geodes; sometimes they also have some other features more often seen in the solid Agates, many are just partially filled.
Ocos or Ochos Geodes -One of the most spectacular occurrences of Geodes are those from the Serra Geral Formation, Rio Grande do Sul, Brazil. Another famous location of Dark Brown and Reddish soil Deposits is the Oco (Ocho) Geode Deposits from Tres Pinheiros, Fountoura Xavier, Rio Grande do Sul, South Region, Brazil.
They have amazing crystal lined hollow centres, lined with clear Quartz crystals that sparkle like cut diamonds in the sunlight. These Oco Geodes, sometimes spelt Ochos are named such because Oco is the Portuguese word fro a hollow stone. They were found abundance in local ploughed fields for many decades, broken open by the plough.
Ocos are found in the weathered volcanic rocks of the area and are between 127 and 138 million years old, dated from the surrounding rock. The host rock is amygdaloidal basalt that has been weathered to produce the dark reddish soil (Cascalho) found in the pampas grasslands of Southern Brazil.
Ocos are discovered scattered amongst the hills in an area called the Three Pines Region about 80 miles northeast of Soledade. Only half of all the Ocos discovered are later found to be actually hollow. These stones often have a classic rope like texture and when removed from the weathered rock; they also have a similar textured interior, when sliced open.
After the rocks have been transported, sometimes by mule, to the town of Solidad, they are then cut in half and polished.
Minerals from Brazil
Minerals and Crystals for Sale
Weight - 50g