To physically transform from one mineral into another.

The process of a rock or mineral being transformed into another one.

Instrument for measuring altitudes or elevations with respect to a reference level, usually mean sea level. The most common type is an aneroid barometer. A radar altimeter determines the height of an aircraft above the terrain by measuring the time required for an electromagnetic pulse to travel from aircraft to the ground and back.

Fossilized pine resin, many times used for ornamental purposes.

Without a crystalline shape.

Individual member of the amphibole group.

Group of minerals that contain iron, magnesium, silicon, oxygen, and hydroxyl (OH). They may also contain calcium, sodium, and lithium. The amphiboles have prismatic cleavage, and one can note the angle of 56° and 124°, which distinguishes it pyroxenes, which are at 87° and 93° (almost perpendicular). The amphiboles are very similar to the pyroxenes, and the minerals belonging to each group many times cannot be distinguished by ordinary methods. Generally, though, the amphiboles occur in longer, thinner crystals than the pyroxenes. The pyroxenes contain the same elements that the amphiboles do, except they lack hydroxyl, which alters both physical and chemical properties. The amphibole group is in the inosilicate subdivision of the silicates group.

Most earthquakes are relatively small, in fact, so small that no one feels them. In order for seismologists to see the recording of the movement of the ground from the smaller earthquakes, the recording has to be made larger. It's like looking at the recording through a magnifying glass, and the amount that it is magnified is the amplification. Shaking levels at a site may also be increased by focusing of seismic energy caused by the geometry of the sediment velocity structure, such as basin subsurface topography, or by surface topography.

The amplitude is the size of the wiggles on an earthquake recording.

A small, bubble-like mass formed from volcanic igneous rock that solidified and a bubble of gas got trapped in the interior.