ZACK'S ROCKS & MINERALS - Facts
The difference between a rock and a mineral is a rock is an aggregate of one or more minerals; or a body of undifferentiated mineral matter.


A mineral is a naturally occurring inorganic element or compound having an orderly internal structure and characteristic chemical composition, crystal form, and physical properties.


Igneous rocks (from the Greek word for fire) form from when hot, molten rock (magma) crystallizes and solidifies. The melt originates deep within the Earth near active plate boundaries or hot spots, then rises toward the surface. Igneous rocks are divided into two groups, intrusive or extrusive, depending upon where the molten rock solidifies.


Of the 193,000 metric tons of gold discovered to date, 62% is found in just four countries on earth. All the gold discovered thus far would fit in a cube 22 meters on a side.


Of the 1,740,000 metric tons of silver discovered to date, 55% is found in just four countries on earth. All the silver discovered thus far would fit in a cube 55 meters on a side.


Of the 1.52 billion metric tons of copper discovered to date, 56% is found in just four countries on earth. All the copper discovered thus far would fit in a cube 550 meters on a side.


Over 50% of all the zinc and lead discovered to date has been found in just four countries on earth.


The largest recorded earthquake in the United States was a magnitude 9.2 that struck Prince William Sound, Alaska on Good Friday, March 28, 1964.


The largest recorded earthquake in the world was a magnitude 9.5 (Mw) in Chile on May 22, 1960.


The largest Earthquake in Virginia was at Giles County, Virginia 05-31-1897 it was a magnitude 5.9. This earthquake was the largest in intensity and aerial extent in Virginia in historical times. MM intensity VII to VIII extended over an elliptical area - from near Lynchburg, Virginia, west to Bluefield, West Virginia, and from Giles County south to Bristol, Tennessee. The MM intensity VIII assigned to this earthquake is based on "many downed chimneys" and "changes in the flow of springs."

The shock was felt severely at Narrows, about 3 kilometers west of Pearisburg. Here, the surface rolled in an undulating motion, water in springs became muddy, and water in some springs ceased to flow. The flow of water in springs also was disturbed in the area of Pearisburg, about 70 kilometers west of Roanoke, and Sugar Run.

The shock was strong at Pearisburg, where walls of old brick houses were cracked and many chimneys were thrown down or badly damaged. Many chimneys also were shaken down at Bedford, Pulaski, Radford, and Roanoke, Virginia, and Bristol, Tennessee; many chimneys were damaged at Christiansburg, Dublin, Floyd, Houston, Lexington, Lynchburg, Rocky Mount, Salem, Tazewell, and Wytheville, Virginia; Charlotte, Oxford, Raleigh, and Winston, North Carolina; Knoxville, Tennessee; and Bluefield, West Virginia. Felt from Georgia to Pennsylvania and from the Atlantic coast westward to Indiana and Kentucky. Aftershocks continued through June 6, 1897.


Earthquakes are recorded by a seismographic network. Each seismic station in the network measures the movement of the ground at the site. The slip of block of rock over another in an EQ releases energy that makes the ground vibrate. That vibration pushes the adjoining piece of ground and cause it to vibrate and thus the energy travel out from the EQ in a wave. There are many different ways to measure different aspects of an earthquake. Magnitude is the most common measure of an earthquake's size. It is a measure of the size of the earthquake source and is the same number no matter where you are or what the shaking feels like. The Richter scale measures the largest wiggle on the recording, but other magnitude scales measure different parts of the earthquake. Intensity is a measure of the shaking and damage caused by the earthquake, and this value changes from location to location.


Mineral elements provide the color in fireworks. Barium produces bright greens; strontium yields deep reds; copper produces blues; and sodium yields yellow. Other colors can be made my mixing elements; strontium and sodium produce brilliant orange; Titanium, zirconium, and magnesium alloys make silvery white; copper and strontium make lavender. Gold sparks are produced by iron filings and small pieces of charcoal. Bright flashes and loud bangs come from aluminum powder.

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