일반명 : 나무화석(Petrifiedwood) Conifers(침엽수)

학명 : Araucaria sp.

지질시대 : Triassic (about 22 million years ago)

지층 : Mahajanga

원산지 : Ambilobe, Madagascar

DESCRIPTION: To help visualize the size of this sp, the US coin (measuring 1 inch / 25 mm) is placed next to the sp, perpendicular to its center. Done this way you can accurately compare the diameter of the quarter with that of the sp This specimen was created in Madagascar from a larger piece of "rough" fossilized petrified wood during a long process that used up many costly cutting blades as well as expensive diesel fuel to run the generator that ran the lathe (the capital of Madagascar receives only a few hours of electricity a day). The wood genus is araucaria (a conifer) and dates to the early Triassic Epoch period, roughly 225 million years ago.

Any "cracks" that you see are naturally occurring fractures that have re-cemented over the eons and thus are stable and in no danger of breaking or shattering. In addition, you'll often see veins of clear quartz crystals and/or crystal-filled cavities. All are natural and unique to each specimen.

Petrified wood is a type of fossil consisting of ancient wood w all the organic materials have been replaced with minerals (usually crystalline quartz), while retaining the original structure of the wood. The petrifaction process occurs underground, when wood becomes buried under sediment. Mineral-rich water flowing through the sediment deposits minerals in the plant's cells, and as the plant's lignin and cellulose decay away, a stone mold forms in its place. Elements such as manganese, iron and copper in the water/mud during the petrification process give petrified wood a variety of color ranges. Since pure quartz crystal is colorless, only when such contaminants are present do the crystals take on a mixture of other colors. The following is a list of contaminating elements and related color hues:

* cobalt - green/blue

* chromium - green/blue

* copper - green/blue

* iron oxides - red, brown, yellow

* manganese - pink/orange