East bound I-80 #1 EarthCache

This is the first earthcache at this rest stop.

Gabbro,  Granite and Basalt are all formed from magma.

When magma becomes trapped “intrusive” (meaning = under the surface layer), it will cool extremely slow and form gabbro. Gabbro’s texture will be even throughout, and the mineral grain size will be very small.

If this same magma gets “metamorphized” (Meaning = pushed up from deeper in the earth’s crust) this pressure will force the component materials to “coalesce” (meaning = combine elements in a mass or whole) forming larger crystals. This process takes a LONG time and is “intrusive” (meaning = under the surface). This will form granite.

But if the same magma cool rapidly because it comes in contact with air or water, which would be “extrusive” (meaning = above ground) it will form basalt. Gabbro is the blackest granite that is possible. Basalt is also black not fails to compare to Gabbro.

Limestone

Is a sedimentary rock composed largely of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate (CaCO₃). Limestone makes up about 10% of the total volume of all sedimentary rocks. The solubility of limestone in water and weak acid solutions leads to karst landscapes, in which water erodes the limestone over thousands to millions of years.

Granite

First, granite is made of large mineral grains (which is where its name came from) that fit tightly together. Second, granite always consists of the minerals quartz and feldspar, with or without a wide variety of other minerals (accessory minerals). The quartz and feldspar generally give granite a light color, ranging from pinkish to white. That light background color is punctuated by the darker accessory minerals. Thus classic granite has a "salt-and-pepper" look. The most common accessory minerals are the black mica biotite and sometimes black amphibole hornblende.

Biotite

Biotite is a common phyllosilicate mineral within the mica group; more generally, it refers to the dark mica series.

(basicly it's the black you see below)

Igneous rock examples

Gabbro

Granite

basalt

**Logging requirements**
DO NOT POST ANSWERS IN YOUR LOG.
Send the following answers to me via email.

1. The text "GC5TM2W East bound I-80 #1" on the first line
2. What is the Length – width – height of the rock?
3. What is the primary color?
4. Based on the above description what type of rock do you think this one is?