Ocos Geodes
SpiritRock Shop
Lot of 3 beautiful Ocos Geode polished halves

-dark grey and white with fine quartz crystals
-reddish brown and white with clear quartz crystals
-Black and white with quartz with inclusions
Click on any photo to see a larger version
Polishers Laps Saws
Official PayPal Seal
Many names have been given to geodes throughout the
world, but none so fitting as the Ocos Geode (some say
these are named for their source, the Orinoco River in Brazil,
others believe it came from the Portuguese word for
"hollow," you decide...)
Ocos formed some 130 million years ago in
basalt amygdules (a formerly open vesicle which has been
filled with a secondary mineral(s) precipitated from low temp
ground waters which penetrated into the rock). Over the
years the basalts have been weathered away and left behind
small geodes in what is now called cascalho, a dark reddish
brown soil in the Serra Geral Formation.
Ocos are mainly found in the 3000 ft elevations of the Tres
Pinheiros (Three Pines) region.  The geodes are normally
removed from the basalt by hand (which can be difficult
because their skin or outer shell of chalcedony is relatively
thin and often rope-like in formation). The Ocos are then
taken back down the steep mountains in burlap sacks or
buckets on horseback or by pack mules to the town of
Soledade to be cut and polished.
Thin shell Ocos called "casa fina" command a higher price,
but display less of the famous wavy or flame like patterns on
the rim. Ocos size is usually small (1-3 inches)
When cut, Ocos display brilliant drusy quartz linings on tan,
grey, brown or black shells with white waves or flames. Many
Ocos have inclusions in the quartz, rarely amethyst.



Item # OG09106030
Lot of 3
Polished Ocos Geode (Half)  
Quantity Available 1 lot
Lot of 6 beautiful Ocos Geode polished halves
-reddish brown with clear quartz crystals
-dark grey and white with fine drusy quartz crystals
-Black and white with very fine drusy with geothite inclusions,
wispy shell with rope formation
-Blackand white with drusy quartz with inclusions
Item # OG09107060
Lot of 6
Polished Ocos Geode (Half)  
Quantity Available 1 lot
Item # OG09101570
Polished Ocos Geode (Half)  
Beautiful roped exterior shell with grey, white and clear wisps on the polished edge with well formed crystals in the interior.
This specimen weighs 6.4 oz (183g) and measures 3.5 x 1.7 x 2.2 inches (9 x 4.3 x 5.6 cm)
Item # OG09107350
Polished Ocos Geode (Half)  
Stunning crystal formation growth with artichoke or Babylon type formations in a natural display amphitheatre
This specimen weighs 4.9 oz (140g) and measures 4.1 x 1.6 x 1.8 inches (10.3 x 4 x 4.4cm)
Item # OG09108350
Polished Ocos Geode (Half)  
Fabulous smoky quartz, clear quartz and drusy quartz line the interior roped formation with pronounced black, white and
clear wisps lining the polished edge of this rare specimen.
This specimen weighs 4.2 oz (119g) and measures 3.9 x 1.6 x 1.8 inches (10 x 4.1 x 4.4cm)
Item #OG09104460
Large Polished Ocos Geode

Deep opening lined with well formed clear quartz dotted with black goethite with small white calcite formation.
This specimen weighs 5.5 oz (156g) and measures 3.1 x 2.1 x 1.6 inches (7.9 x 5.3 x 4cm)
Item # OG09109350
Large Polished Ocos Geode

Weather worn roped smooth exterior with larger smoky quartz crystals lining the interior of this magnificent specimen!
This specimen weighs 4.4 oz (126g) and measures 3.6 x 1.7 x 1.5 inches (9.2 x 4.3 x 3.7cm)
Item # OG09106690
Polished Ocos Geode
(Half) with pewter
Roped exterior with drusy smoky quartz crystals with black and white wisp swirls are the backdrop setting for this
lucky prospector with his pan. Beveled edge glass stand glued to bottom of geode.
This specimen weighs 4.8 oz (136g) and measures 3.1 x 1.9 x 2 inches (7.8 x 4.7 x 5.6cm)