Slow Heart Beat (Bradycardia) An abnormally slow sinus heart rate is called the âsick sinus syndromeâ and, if severe, results in symptoms of fatigue. In some such cases a permanent pacemaker is needed to be implanted to generate a normal heart rate. Many people with sick sinus syndrome also develop atrial fibrillation.
Petrified wood (from the Greek root petro meaning rock or stone; literally wood turned into stone) is the name given to a special type of fossilized remains of terrestrial vegetation. It is the result of a tree or tree-like plants having completely transitioned to stone by the process of permineralization.lements such as manganese, iron, and copper in the water/mud during the petrification process give petrified wood a variety of color ranges. Pure quartz crystals are colorless, but when contaminants are added to the process the crystals take on a yellow, red, or other tint.
A wide variety of names are commonly used for petrified wood. Fossilized wood is a general term for wood that has been petrified or preserved by other methods of fossilization. Opalized wood is petrified wood that has been replaced by opal, an amorphous form of silica.Agatized wood is wood that has been replaced by agate, a form of chalcedony or microcrystalline quartz.mall pieces of petrified wood can be placed in a rock tumbler to make tumbled stones. Only a small fraction of petrified wood is suitable for lapidary work. Poorly preserved specimens, those with lots of voids or closely-spaced fractures do not polish well or break while being worked.