Two types: Sender & Reciever Bought from Jeweler. Sender is 68gp and comes with 500 charges. Reciever is 34gp.
The reciever doesn't use charges, and by placing gems on a sender, one can recharge...charges. Recieved messages can be used with the "If Sysmessage=" command within the Razor Script System.
Each crystal can broadcast a message to several crystals. To link a crystal to send to another crystal, use the sender crystal and target the receiving crystal. Com crystals can only be linked to other com crystals. To turn on a crystal, use the crystal and target itself. It will turn red. Do the same thing to turn the crystal off (it will turn green again). When a crystal is on, it will send anything that is said around it to all crystals it is linked to. Each message sent to a crystal will cost a charge (ex: a crystal linked to 3 other crystals will use 3 charges each time something is spoken around it). If a crystal is on and inside a backpack or container, it will still send messages.
When someone sends a message, the receiver crystal will bark their name and their message if on the ground. If the crystal is contained by a player, the player will see the message as a system message at the bottom of their screen. Receiving a message does not use any charges on the receiving crystal.
To recharge a crystal, use the crystal and target a gemstone. The crystal will destroy the gemstone and regain some charges. Different types of gemstones recharge different amounts of charges (generally, the more expensive the gemstone, the more charges it gives). Crystals can hold a max of 2000 charges, and any extra charging beyond 2000 will just be wasted.