|“||Silver for the demon towers.||”|
–Old Nephilim children's rhyme, The Shadowhunter's Codex
The towers are formed of pure adamas. However, unlike other examples of worked adamas, the towers are special in that their glow does not diminish with use, and their power does not need to be refreshed. The adamas of the tower also makes it appear pale silver-white.
The demon towers are tall and shoot up into the sky. It is for the towers' clear adamas and over-all glass-like appearance that Alicante was dubbed a "city of glass."
As previously mentioned, the towers reinforce the wards around the city. The wards were set up in such a way that the use of demon blood within the city is the only way to take them down and it seemed to be the perfect paradox since demons cannot enter Alicante because of the wards the towers control.
The adamas of the towers also make them shimmer or shine in the sun and moonlight, making it a form of source of light for the streets at night.
As an additional precautionary measure, the towers light up in different colors as warnings depending on the situation; an example is their red and gold battle lights that signal the people of Alicante to get to the Gard, and blue for the Accords or as a sign to listen to their leader.
According to the accounts of Jonathan Shadowhunter, the towers were created by Raziel and given to the Shadowhunters along with Idris and Alicante themselves, that they apparently grow out of a thick vein of adamas placed by Raziel under the earth to be mined for weapons and tools. The demon towers have stood unchanged for centuries, and the Nephilim's scholars have been unable to determine the towers' mysteries.
Fortified for years, the city was caught by surprise when Valentine's demon army was able to enter Alicante, after Sebastian Morgenstern climbed the towers and used his demon blood to deactivate them from within the city in September 2007.
- Similar structures can be found surrounding the Gard, where four smaller towers rise from the four cardinal points of the Gard, and the Adamant Citadel, with its ring of towers, though these are man-made, less graceful, and tipped with electrum.