P 17 Posts in this encyclopedia category
Petrified or silicified wood
Petrified silicified wood Silicification is the impregnation or conversion of a naturally occurring mineral or organic material with or into microcrystalline silicon dioxide (SiO2). The...
Pietersite
Pietersite was first discovered at the end of the 20th century near Outjo/Namibia. Pietersite is a rubble stone of tiger's and hawk's eye, and was named after the trader Sid Pieters, who first...
Prasem stone
The name prasem was used in the Middle Ages and still today to describe all base green quartz. Prasem is a coarse or crystalline quartz, with green actinolite inclusions. Synonyms are...