The temple jewels are green-glowing orbs pierced on top of stone pedestals with two stone circles around them. Despite their primitive look, they are actually power sources, each capable of powering one of the Black Arms' temple-based aircraft fortresses, helping keeping them afloat. According to Dr. Eggman, the temple jewels emit a high-energy magnetic field.
According to Black Doom, the temple jewels were brought to Earth by himself 2000 years ago alongside the temples themselves in preparation for his invasion of the planet.
In Glyphic Canyon, the Dark Mission requires Shadow to activate five temple jewels in order to get the Black Arms' temples into the air. To activate them, Shadow just has to touch them. Later on in Sky Troops, regardless of whether or not Shadow activated them prior, the temple jewels are already active. In Sky Troops, the Hero Mission requires the player to destroy five temple jewels in order to cause the temples to collapse.
These temple jewels resemble the Master Emerald in function: both are used to keep large landmasses afloat.
↑Kaizen Media Group (22 November 2005). "Sky Troops". Shadow the Hedgehog: Prima Official Game Guide. Prima Games. p. 35. ISBN 978-0761551959.
↑Sonic Team (15 November 2005). Shadow the Hedgehog. GameCube. Sega. Stage: Glyphic Canyon. "Black Doom: Next, you must find the jewel that is key to the reawakening our temple, and release its power. / ... / Black Doom: Our first temple has awakened. Can you not feel that shockwave?"