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Taking Time for Granite Earthcache

A cache by PathfinderMark Send Message to Owner Message this owner
Hidden : 11/10/2009
1 out of 5
1 out of 5

Size: Size:   not chosen (not chosen)

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Geocache Description:

As an earthcache, there is no “box” or “container” to discover. Rather, with this cache, you discover something about the geology of the area. For more info, consult

This earthcache is handicap accessible from the sidewalk.

It is located At a Vallejo marina, near a ferry port.

You are looking at a chunk of granite. It is obvious that the granite is “erratic” at this location, that is, it was brought here by man or nature, and does not naturally occur at this location – a beach in Northern California. In fact, it has been extensively worked by mankind at this location.

Granite is an igneous rock that is composed primarily of four minerals. The term "Granite" is derived from the Latin word "Granum" meaning "grain" because of its granular nature. During Earth’s childhood, magma cooling very slowly far under the planet’s surface, allowed crystals of four minerals to grow large enough to be easily seen by the naked eye. These minerals are quartz, feldspar, mica, and usually hornblende. However granite is not a homogenous rock and it's composition varies depending on its location. Other less common components give granite a wide variation in look and color.

Granite is light in color because it is composed largely of minerals that are rich in silica. These include quartz, feldspar (orthoclase and plagioclase), and muscovite (a mica). Quartz is milky white, feldspars are pink, white, or gray, and muscovite is silvery. The dark color of granite comes from dark colored minerals, including hornblende, augite, and biotite (another mica). These minerals are green, brown, and black in color.
Granites actually come in many different colors. This variety in granites is caused by differences in mineral composition, especially in the feldspars. If feldspars are potassium-rich (orthoclase) the granites may be tan to reddish in color. If feldspars are calcium-rich (plagioclase) light to dark gray colored.

Granite is used as a building material in the form of granite tiles and granite slabs for wall cladding, roofing and flooring and a variety of other interior and exterior applications and especially for counter tops, kitchen work tops and vanity units and is the most popular material for monuments and memorials.

Logging Requirements:
Send the answers to #1-#4 to me through my geocaching profile.

1. List the name “GC20WYJ Taking Time for Granite Earthcache” in the first line of your email. Also, list the number of people in your group.
2. What color and shape is this chunk of granite?
3. Based on the color is the feldspar calcium rich (plagioclase) or potassium rich (orthoclase)?
4. Granite has a mass/weight of 166.5 lbs/cubic foot. Using the following formulas as appropriate {mass(weight) = lwh} for rectangles/squares and {1/3 lwh} for pyramids, {3.14rh} for cylinders, tell me how heavy the rock is! You will need to presume that the object is solid granite for this calculation.
5. (Per current guidelines, photos are no longer allowed to be required. HOWEVER they are encouraged, since they can help clarify that you have visited the location if your other logging requirement answers are vague). Post a picture of yourself and your GPS with your log that shows the waterfront in the background. DO NOT show any of the pertinent information in your picture or your log may be deleted.

I will only respond if you have incomplete logging requirements. Go ahead and log your cache

Additional Hints (No hints available.)

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