Gemstones are the signature part of any Gem. They appear as literal gemstones in various cuts, shapes, and colors located on a part of a Gem's physical form.
Gemstones are, in essence, the Gem being itself. Their physical bodies are merely a projection with mass from within the gemstone, much like their weapons and outfits. If the physical body (which is just an illusion) of a Gem is severely damaged or injured, it retreats to its gemstone to regenerate and project a new body form.
In contrast, any slight damage to the gemstone, such as a crack, results in a serious and crippling injury to the Gem. It can interfere with their magical Gem powers. It also interferes with their ability to manifest/control their physical bodies. Destroying a gemstone effectively kills the Gem (although it retains some magical properties).
During Gem fusion, all participants' gems shift colors to match each other. If the participants of the fusion are the same Gem type, the resulting fusion is just a larger version of the Gem.
Multiple Gems with the same gemstone may exist. Gemstone placement appears to vary from Gem to Gem, even if they are of the same gemstone.
Gems can manifest things from within their gemstone; the most important being their personal weapons and their physical bodies. Gems also have the ability to store and withdraw objects in their gemstone.
Gem bubbles have a stasis-like effect on gemstones; when "bubbled" by another Gem, the gemstone is prevented from regenerating/manifesting its physical body or weapon, essentially being imprisoned indefinitely until the bubble bursts.
Gemstones also find a use in Gem technology. They are used as power sources for various objects.
As one would expect, the gemstone of each individual Gem is a core aspect of Gem culture. Gems are not only named after their gemstone, but are also recognized by other Gems by it. Individuality is a rare concept among Gems, as there is little to differentiate Gems (aside from type) than a serial number based on facet and cut.
|Pearl's gemstone is located in the center of her forehead. The gemstone is smooth with no facets. It has a silver ring around the edge which is usually hidden inside her forehead.||N/A|
|Amethyst's gemstone is located on her chest. It has a hexagonal facet. It has a silver ring around the edge which is normally hidden inside her body unless she's regenerating.||N/A|
|Rose Quartz's gemstone, along with Steven's, is located on their navels. It has a pentagonal facet.||N/A|
|Sapphire's gemstone is located on the palm of her right hand. It has a triangular facet. It has a light blue ring around the edge (normally hidden inside her hand), and is flatter on the back.||N/A|
|All Rubies are known to share the same gemstone. It has a square facet. It has a light red ring around the edge (normally hidden inside their body), and is flatter on the back.||AlexandriteTheCrystalFusion|
|Lapis Lazuli's gemstone is located in between her shoulder blades. Her gemstone is smooth with no facets.||AmethystPearlFusion|
|Peridot's gemstone is located in the center of her forehead. Her gemstone has facets around the edge.||N/A|
|Jasper's gemstone is located where her nose would be, in the center of her face. Her gem is cut with a point that is the conversion of the other three facets.||Jaspy-Jaspers|
|Blue Diamond's gemstone is located on her chest, featuring a diamond-shaped facet, and a diamond shape overall.||AmethystPearlFusion|
|In the fashion of her owner, Blue Diamond, Blue Pearl's gem, a powder-blue pearl, is on her chest and is a round polished cabochon.||Rena-Shi|
|Located on her right cheek, Cheeky's gemstone is located on her chest. It has a hexagonal facet. It has a silver ring around the edge which is normally hidden inside her body unless she's regenerating.||Jaspy|
|Yellow Diamond's gemstone is located on the center of her chest. It is shaped like an equadilateral diamond, and has four facets with a smaller sized diamond-shaped center facet.||Golden Forge|
|In the fashion of her owner, Yellow Diamond, Yellow Pearl's gem, a yellow pearl, is on her chest and is a round polished cabochon, similar to Blue Diamond's Pearl.||Rena-Shi|
|Bismuth's gemstone is located on her chest. The gemstone itself is hollow, and each "layer" of the gemstone is a different color of the rainbow.||AmethystPearlFusion|
|White Diamond's gemstone is located on her forehead, cut to a distorted rhombus with an identical facet.||Rena-Shi|
|Sapphire's gemstone on Garnet.||N/A|
|Ruby's gemstone on Garnet.||N/A|
|Pearl's gemstone on Opal.||N/A|
|Amethyst's gemstone on Opal.||N/A|
|Pearl's gemstone on Rainbow Quartz.||N/A|
|Rose's gemstone on Rainbow Quartz.||N/A|
|Jasper's gemstone on Malachite.||N/A|
|Lapis Lazuli's gemstone on Malachite.||N/A|
|Pearl's gemstone on Sardonyx.||N/A|
|Sapphire's gemstone on Sardonyx.||N/A|
|Ruby's gemstone on Sardonyx.||N/A|
|Amethyst's gemstone on Sugilite.||N/A|
|Sapphire's gemstone on Sugilite.||N/A|
|Ruby's gemstone on Sugilite.||N/A|
|Pearl's gemstone on Alexandrite.||N/A|
|Amethyst's gemstone on Alexandrite.||N/A|
|Sapphire's gemstone on Alexandrite.||N/A|
|Ruby's gemstone on Alexandrite.||N/A|
|Steven's gemstone on Stevonnie.||N/A|
|Amethyst's gemstone on Smoky Quartz.||N/A|
|Steven's gemstone on Smoky Quartz.||N/A|
|Sea Salt Pearl's gemstone on Sky Blue Opal.||AmethystPearlFusion|
|Dark Violet Amethyst's gemstone on Sky Blue Opal.||AmethystPearlFusion|
|Emo Ayanite's gemstone on Ayanite Fusion.||AmethystPearlFusion|
|Ayanite's gemstone on Ayanite Fusion.||Pepearl|
|Paddy's gemstone on Crimson Sapphire.||AmethystPearlFusion|
|Midnight Sapphire's gemstone on Crimson Sapphire.||Jaspy-Jaspers|