Although to the naked eye the One Ring looked like a normal gold ring, it was immune to all forms of destruction, except for the fires of Orodruin (Mount Doom), the volcano located in the land of Mordor, where it was forged by Sauron. It was possible to identify it by subjecting it to intense heat, since in this way an inscription appeared in the black language of Mordor, written in tengwar characters on both the internal and external faces of the Ring, and symbolizing its power to control the other Rings of Power. .
The translation that the wizard Gandalf made of this phrase is:
One Ring to rule them all, One Ring to find them,
a Ring to attract them all and bind them in the darkness.
In Sauron's hands the Ring was easily recognizable, since the intense heat given off by its body was enough for the inscription to glow continuously.