Aquamarine forms when magma under the Earth's crust interacts with mineral-rich rocks under mountain ranges. The magma cools as it enters fissures and crevasses of rocks called pegamites. The minerals in the pegamites he... More »

Some semi-precious stones are amethyst, opal, tanzanite, pearl and onyx. Garnet, moonstone, turquoise and peridot are also considered semi-precious. The expansive list also includes tiger's eye, topaz, coral, malachite a... More »

www.reference.com Beauty & Fashion Jewelry & Watches Precious Metals & Gems

The four precious gemstones -- diamonds, rubies, emeralds and sapphires -- symbolize power, strength, and prosperity. Semi-precious gemstones such as aquamarines and citrine vary in their symbolism, but are typically ass... More »

www.reference.com Beauty & Fashion Jewelry & Watches Precious Metals & Gems

The chief difference between a volcano and a mountain is that a volcano forms around a vent that allows magma to reach the surface of the Earth, while a mountain can be formed by a variety of different geological process... More »

An upwarped mountain is a mountain formed from force created by heat or magma pushing up directly under the Earth's crust. The force lifts the layers of rock in the Earth's crust above ground level. More »

Granite and gabbro are igneous rocks formed through the cooling and crystallization of magma in the Earth's crust. They are identified by their specific mineral content and composition. More »

Rocks formed from magma in the Earth's mantle are called igneous rocks. However, there are different types of magma. Lava rocks can be basalt, andesite or rhyolite. More »