Pendant of Skill was discontinued from RuneScape after an update, but still exists in-game.
Pendants of Skill are members-only items that give the player a boost in the Experience earned the associated skill. These can be obtained via Squeal of Fortune, either directly or as a prismatic pendant that can be changed to any skill-specific pendant. Any pendant, charged or uncharged, can be destroyed for a cosmetic version that may be re-obtained from Diango in Draynor Village. Players can obtain a new pendant of the same type as a pendant they already have, as long as the old pendant has been destroyed.
Unlike most items, pendants may be brought into and back out of Dungeoneering. In general, pendants do not increase special experience rewards given by Distractions and Diversions or minigames, but they may give extra experience for activities (such as combat) performed inside such an event.
The bonus experience gained from a pendant is dependent on the relevant level. Experience from a normal pendant is equal to 1.2x the experience of a large XP lamp, and experience from a prized pendant is equal to 1.2x the experience of a huge XP lamp.
Now, players can "Claim xp" from a pendant, adding the remaining experience as bonus experience and turning the prized pendant into a cosmetic pendant of skill.
The colours of the pendants are meant to contain the colours of the skillcapes which their skills represent. Some of the pendants have slightly off colours, however. (Fletching is baby-blue and white instead of dark teal and gold, Dungeoneering is brown and light brown instead of reddish-brown and light orange)
The pendants have the same graphical effect as the Mad Necklace when equipped and un-equipped.
You are able to convert a prismatic pendant into a pendant you already own (e.g. Pendant of Agility) only if said pendant is with Diango.