What are the Origins of Gems?
The origins of these precious materials come from the rocks that surround us and go deep into the earth. The majority of gemstones began their lives as mineral crystals shaped by thousands of years of geological changes. Today these crystals are mined, cut, faceted and then polished for use in jewelry and decoration.
What is an Organic Gem?
The basis of organic gems is based on biologically obtained materials. Amber stone, a kind of fossilized tree resin, and pearls produced by oysters with minerals obtained from the sea are examples of these organic gemstones. However, the financial and perceived value of gemstones may differ between societies. For some societies, jade is considered more valuable than gold. In addition, ruby is among the most precious stones for Western societies. Designed as a ring by Cartier, the 25.6-carat "Sunrise Ruby" sold for approximately $30 million in 2015.
Where Do the Minerals Come From?
Most gemstones consist of crystals cut from minerals. A mineral is defined as a naturally occurring solid structure that has a specific chemical composition and a distinctive crystalline structure. Each mineral has a unique name given in line with these two important criteria. If the chemical composition or crystal structure of the mineral changes, it becomes a different mineral, hence this new mineral is given a different name.
How Many Rock Types are found on Earth?
Rocks are grouped into three main classes: igneous, sedimentary and metamorphic. Igneous rocks are formed from magma, meaning molten rock. Magma solidifies underground to form rocks such as granite, or it flows onto land or to the seafloor, yielding extrusive rocks such as basalt. On their surface, tiny crystals may be seen.
Most sedimentary rocks are formed from sediments left on the Earth's surface by wind, water, or ice. Sandstone is an example of sedimentary rocks. Sandstone is mostly composed of quartz, however other minerals might be included. This sample has areas of iron oxide and mica flakes. Metamorphic rocks are formed as a result of changes in the mineralogical composition of existing rocks by pressure or heat. Quartzite stone is sandstone that has been metamorphosed in this way. Gneiss component minerals tend to split into discrete bands of varying hues.
What is an Organic Rock?
There are also some rocks composed of organic matter. Coal is an organic rock formed by the alteration of decayed vegetation over many years. The majority of Earth's rocks are, on the other hand, composed of naturally occurring aggregates of one or more minerals.
What is a Rock Cycle?
The rock cycle results in the creation of rocks and minerals. All rocks are igneous at first, but throughout time they undergo weathering, remelting, or erosion. Sedimentary rocks were created as a result of erosion, and at the right pressure or temperature circumstances, they can transform into metamorphic rocks.
