Petrified wood collections are usually dominated by sliced and polished pieces, and loaded with colorful variations of the same wood from the same predominant sources in the world. Advanced collectors strive to include specimens that are in their natural form and more importantly, from rare deposits. This set of two pieces fits BOTH of those descriptions. These are two completely natural as collected, fragments from a petrified tree, that were found in the Sahara Desert. They were acquired from a very old private French collection of a former safari guide to the Tenere Region of the South Central Sahara Desert. Both pieces show nice detail and are extremely scarce! They were surface collected many decades ago amongst Super Croc and dinosaur fossil remains laying exposed in the Sahara of Niger. in 32 years of our experience in this field, these are are one of very few pieces we ever saw of its kind from this region of the world. NO REPAIR, POLISHING, ALTERATIONS OR RESTORATION.
The South Central Sahara Desert used to be lush and green with forests, plains and swamps. In the recent past, a human occupation site was discovered by paleontologist Paul Sereno with his works published referencing the "The People of the Green Sahara". Early human prehistoric stone tools made of petrified wood like this, have been found that date from the Acheulian to the Neolithic Periods, in the region from where this fossil log was found. There are areas in the Sahara that show multiple petrified trees that are the remains of entire forests once alive in prehistory.
This source and type of petrified wood was a prized and rare material used in Paleolithic stone tools of various prehistoric African cultures. The petrified wood was prized for the aesthetic bullseye grain patterns that were incorporated in the stone tool design by primitive humans of the region, in their Stone Age tool-making!
Petrified wood in its natural form is MUCH LESS prevalent on the market compared to sliced and polished examples. Unfortunately, when such modifications are done to the specimen, the fossil value of the wood is lessened and the piece becomes more of a pretty mineral showpiece rather than an educational and intriguing display fossil because the natural interior and exterior appearance has been modified or in some cases, destroyed.
Petrified wood forms when real wood lies buried underground and its organic structure is gradually replaced with hard mineral. This petrification requires rapid burial of the wood to prevent normal decay. This can happen in different ways. A flooding river can have bury the forest floor under a layer of sand and silt, for example. Another circumstance could occur when forests are covered by volcanic ash. After burial, mineralized groundwater begins to percolate through the wood, coating cell walls and filling the intercellular cavities with stone. In some cases, the entire log is converted to stone and is solid like a cast of the original piece. In other cases, the delicate cellular structures are preserved along with growth rings, bark and knots such that the petrified wood exactly resembles modern wood yet is heavy as stone when held, and clinks like porcelain. Such detailed preservation is possible because the organic wood molecules become coated and surrounded with smaller silica molecules. Small amounts of impurities in the mineralized water add color to the fossilized wood. The hues of yellow, brown and red indicate iron while black and purple are derived from carbon or manganese.