Translation of comer. On the contrary, Swiss like to isolate themselves from the rest, maybe because the believe that they are superior or better, or maybe because they are just afraid of the unknown, change is not happening.ranslation of comer. On the contrary, Swiss like to isolate themselves from the rest, maybe because the believe that they are superior or better, or maybe because they are just afraid of the unknown, change is not happening.
Dark colored igneous rocks are high in iron and other heavier elements: ma-fic, magnesium-iron. Light color igneous rocks are high in aluminum and potassium. .ou need to understand one of the fundamental differences between mafic and felsic rocks. Mafic rocks contain larger amounts of Mg and Fe than felsic rocks. The atomic weights of Mg and Fe are higher than Al, Si, and O, therefore they tend to be heavier. Very simple concept.
Some extrusive igneous rocks cool so rapidly that crystals do not develop at all. These form a glass, such as obsidian (Figure 4.14). Others, such as pumice, contain holes where gas bubbles were trapped when the material was still hot and molten.The holes make pumice so light that it actually floats in water. The most common extrusive igneous rock is basalt, a rock that is especially common below the oceans (Figure 4.15).Figure 4.13: Extrusive igneous rocks form after lava cools above the surface. The lave spills out from the Earth at a volcano.he holes make pumice so light that it actually floats in water. The most common extrusive igneous rock is basalt, a rock that is especially common below the oceans (Figure 4.15). Figure 4.13: Extrusive igneous rocks form after lava cools above the surface.