GEOLOGY ROCKS - San Pasqual Store

Mineral Mania

SAN PASQUAL STORE

Geology is the study of the Earth and its life, especially as recorded in rocks. Rocks keep record of the passage of time, of great upheavels and profound metamorphosis, even the evolution of living things. Rocks remember, but, to understand their story, you must learn the language of rocks. Geology holds the key to understanding. Learn to listen to rocks and you will unlock the Book of the World!

Rocks are minerals, but not all minerals are rocks. Minerals are all substances that can't be classified as "animal" or "vegetable". Minerals occur as useful metals like gold, silver, copper, and iron. Minerals include everyday items like salt, sand and clay as well as precious jewels like diamonds and rubies. Homogenous natural substances, like water and gas, are also minerals. Of course, these non-solid minerals are not considered "rocks".

Minerals are a huge part of our everyday life. Just take a geological stroll down the supermarket isles and you will find minerals like salt in almost every package of food on the shelves, as well as calcium in the dairy section, potassium over in fresh produce, aluminum on the soft drinks isle, clay in the pet section, and fluoride over on tooth care. Glass and plastics are made from minerals. Even your coin purse is full of minerals! And that is only a sampling of the Earth's treasures that we "mine" for our convenience. Look around the room right now. How many things are made from metal, plastic, or glass? Our lives would be very different if we didn't use anything made from these materials. You may even conclude that minerals are the foundation of the technologies that shape our lives. Come to think of it, if it weren't for a mineral called silica, I wouldn't be creating this Web page because there probably wouldn't be affordable personal computers, much less the World Wide Web!!!

Minerals are essential to Life itself. The small amounts of salt, calcium, potassium, and other minerals that we get from the earth through food maintain our good health and even the physiological functions that make life possible! You and the Earth are both mineral masterpieces.

Rocks are solid mineral deposits found in large quantities in the earth's crust. Minerals require time and the influence of harsh external forces to form into rock. Temperature, pressure, erosion, and friction are forces that effect the formation of rocks. The formation process allows geologists to classify rocks into three groups: igneous, sedimentary, and metamorphic.

Deep inside the earth, temperatures are so extreme that minerals melt into a red-hot liquid called magma. Magma slowly rises toward the surface of the earth. Some magma will cool slowly within pockets deep in the earth. More will continue to flow upward and when the magma finds a weak spot in the earth's outer layer, it pushes its way through. Geologists call magma that flows onto the earth's surface lava. When the molten lava contacts air or water on the surface, it rapidly cools to a solid state. Igneous rock, such as granite, forms when superheated minerals are cooled.

Rock flows are brought to the surface and broken apart by earth movements. Ice, water, wind, plants, and animals- all are forces that wear away rocks, eventually breaking them down into mineral particles like sand and pebbles. Water and wind deposit mineral particles, along with small pieces of shell, bone, and plant parts (collectively called sediment), in layers along lake bottoms, deltas and ocean beds. As more and more sediment piles up, over thousands and thousands of years, the weight of the top layers presses the lower layers into "recycled" rocks. Sedimentary rock, like sandstone and limestone, is commonly found in and around riverbeds and often looks a bit like an earth sandwich - a layer of this, a layer of that.

Metamorphic rock forms when igneous and sedimentary rocks are transformed from one structure to another. Pressure, heat, and time are all required to achieve metamorphosis. For example, igneous rocks buried deep in the earth are squeezed together for millions of years until they have compacted into a more crystalline condition. Marble and slate are two examples of metamorphic rock. Top of Page

RockHound 101 · Mineral Mug Shots · About Us · Maniac Main Page

SAN PASQUAL STORE