ROCKS & MINERALS
A popular, translucent variety of microcrystalline quartz, agate forms when silica from groundwater is deposited in concentric layers around the walls of igneous rock cavities, or in horizontal layers building up from the bottom of the cavity. This process produces agate’s characteristic banded patterning which comes in a variety of interesting colours that are caused by impurities. The Opal Centre has a wide range of polished agate bookends, slabs and slices.
Geodes are rounded, hollow voids in rocks filled with crystals and other minerals. They are typically formed when air bubbles inside of volcanic rock form hollow cavities. Over time, as mineral-rich water seeps into the rock it begins to deposit tiny crystals on the sides the hollow cavity. The most widely known and sought-after geodes are those that formed in areas of volcanic activity.
A meteorite is a solid piece of debris from an object, such as a comet, asteroid, or meteoroid, that comes from outer space and survives its journey through the atmosphere to reach the surface of a planet or moon. Meteorites can break up into several pieces while still in flight or when they hit the Earth. They can travel at very high speeds, typically from about 15 km - 70 km per second. Meteorites range in size from pea-sized pieces up to large masses many tonnes in weight.