Why is Soapstone Slippery?

[caption id="attachment_8570" align="alignright" width="440"] A 12th century soapstone Byzantine relief.[/caption] Most rocks are rough to the touch. Some are smooth. Asbestos is stringy. Sulfur is brittle. One very interesting rock variety is soapstone. It is called smooth and slippery. What makes soapstone slippery? I was raised in the North then moved to the South to where soapstone is is mined, Nelson County, Virginia. I take special interest in the stuff. As a young child, I watched spellbound as my father took a handheld soapstone and used it to sharpen our enormous carving knife. General Rock Types As kids we were taught there are three types of rock, sedimentary, igneous, and metamorphic rock. Sedimentary rock forms from mineral and organic materials near at earth's surface. These deposits form rock deposits over…
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Comparing Hemoglobin and Chlorophyll

Biology, Medicine
[caption id="attachment_7766" align="alignright" width="440"] Hemoglobin tetramer ribbon CC-by-SA3.0 Zephyris[/caption] Are there similarities between the plant and animal world, for instance, between hemoglobin and chlorophyll? In nature, one can expect many parallels. Many animals have four feet. There are apes, lions, camels, and tortoises. Are all these related? Not really. Again, nearly all animals have two eyes in their head. Is there significance beyond the fact that this enables stereoscopic vision along an excellent line-of-sight? And so we come to the two substances most closely associated with life processes: the chlorophyll of plant life and the hemoglobin of animal life. Chlorophyll produces the food plants need for survival. Hemoglobin carries nutrients and oxygen essential to animal life. Although animals and plants are different, there are interesting parallels to be seen in…
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