QUARTZ:
Quartz is the name given to very pure silicon dioxide (SiO2) crystals.
It is a hard, crystalline mineral composed of silicon and oxygen atoms.
There are many different varieties of quartz, many of which are
semiprecious stones. Since ancient times, varieties of quartz have been
among the most commonly used minerals for making jewelry and hard stone
carvings, especially in Eurasia.
QUARTZ FORMATION:
While the majority of quartz crystallizes from molten magma, most quartz
also precipitates chemically as gangue from hot hydrothermal veins,
sometimes with ore minerals such as gold, silver, and copper. Large
quartz crystals are found in igneous pegmatites. Well-formed crystals
can reach several meters in length and weigh hundreds of kilograms.
PETRIFIED WOOD:
Petrified wood, also known as petrified tree, is the name given to a special type of fossilized wood, the fossilized remains of terrestrial vegetation.
The petrifaction process occurs underground, when wood becomes buried in water-saturated sediment or volcanic ash.
Their age can range from 20 million years to 300 million years.