Kimberlite garnets rich in chromium, are generally absent from most other igneous rocks, making them particularly useful as indicators for kimberlites. These indicator minerals are generally sought in stream sediments in modern alluvial material. Their presence may indicate the presence of a kimberlite within the erosional watershed that produced the alluvium. The geochemistry of Kimberlites is defined by the following parameters: Kimberlites are the most important source of primary diamonds. Many kimberlite pipes also produce rich alluvial or eluvial diamond placer deposits. About 6,400 kimberlite pipes have been discovered in the world, of those about 900 have been classified as diamondiferous,
Types of volcanic eruptions general mass behind it moves forward. Pahoehoe lava can sometimes become A'a lava due to increasing viscosity or increasing rate of shear, but A'a lava never turns into pahoehoe flow. Hawaiian eruptions are responsible for several unique volcanological objects. Small volcanic particles are carried and formed by the wind, chilling quickly into teardrop-shaped glassy fragments known as Pele's tears (after Pele, the Hawaiian volcano deity). During especially high winds these chunks may even take the form of long drawn-out strands, known as Pele's hair. Sometimes basalt aerates into reticulite, the lowest density rock type on earth. Although Hawaiian eruptions are