Spessartine is an orange garnet found as crystals in granite pegmatites. Pyrope is a red garnet that is brought to Earth's surface in pieces of peridotite that were torn from the mantle during deep-source volcanic eruptions. Garnet is also found in basaltic lava flows. Garnet in Sedimentary Rocks and Sediments. Garnets are relatively durable minerals.
https://geology.com/minerals/garnet.shtml
1 Magnetism in GemstonesAn Effective Tool and Method for Gem Identification. 2  Garnets are some of the most magnetic gemstones, and magnetic testing gives us rare insights into the world of Garnets, revealing how the different species and varieties of Garnet are related. For most people, the term Garnet brings to mind a dark red gem, but Garnets are in fact a diverse group of gemstones, with more species and color varieties than any other type of transparent gemstone.
https://www.gemstonemagnetism.com/template.html
Red almandine is the red garnet most often found in jewelry because it is abundant and inexpensive. Pyrope and spessartine are reddish garnets that are commonly encountered in jewelry for the same reason.
https://geology.com/minerals/garnet.shtml
These minerals are found throughout the world in metamorphic, igneous, and sedimentary rocks. Most garnet found near Earth's surface forms when a sedimentary rock with a high aluminum content, such as shale, is subjected to heat and pressure intense enough to produce schist or gneiss.
https://geology.com/minerals/garnet.shtml
Some Garnets change color from daylight to incandescent light, much like Alexandrite. There are also hundreds of more subtle color variations among gem-grade Garnets. Some varieties have only been discovered in the last few decades, and some are among the world's rarest gemstones.
https://www.gemstonemagnetism.com/template.html
The Garnet Group: This chart summarizes the members of the garnet group that are most important as gemstones. The aluminum garnets are normally red in color with a higher specific gravity and hardness.
https://geology.com/minerals/garnet.shtml
Quick Links. It is important to distinguish where gems are formed from where they are found. Almost all gems are formed below the Earth's surface. Some are brought to the surface through mining. Some are brought to the surface through earth processes (faulting, folding, large scale uplift, volcanism).
http://nature.berkeley.edu/classes/eps2/wisc/Lect3.html
In summary, gems are not always found where they were formed, nor are they formed where they're found!
http://nature.berkeley.edu/classes/eps2/wisc/Lect3.html
Where do gems form? & Where are they found? Quick Links: Gems form in many different environments in the Earth. We will examine the most common and important environments and formation processes in this lecture. It is important to distinguish where gems are formed from where they are found. Almost all gems are formed below the Earth's surface. 1  Some are brought to the surface through mining. 2  Some are brought to the surface through earth processes (faulting, folding, large scale uplift, volcanism). These processes can move rock up from more than 400 km below the surface.
http://nature.berkeley.edu/classes/eps2/wisc/Lect3.html
Minerals found in these rocks might include gems such as garnet and cordierite. This movie shows metamorphism of rocks resulting from continent-continent collision associated with a subduction zone. Note the formation of large crustals such as garnet in the deformed, heated zone. This movies illustrates the process of contact metamorphism. This is the process by which the minerals in rocks change in response to proximity to a hot intrusive body.
http://nature.berkeley.edu/classes/eps2/wisc/Lect3.html
where in the world can garnets be found
Most garnet found near Earth's surface forms when a sedimentary rock with a high aluminum content, such as shale, is subjected to heat and pressure intense enough to produce schist or gneiss. Most garnet found near Earth's surface forms when a sedimentary rock with a high aluminum content.