Long-range communication stones are palm-sized, triangular devices with rounded edges and intricate designs on the top. They work by forming a psychic link to the last person to make physical contact with them. A second link is established with a nearby stone if applicable, allowing the two users to share thoughts, either conscious or not. The link from the stone to its user requires close range, not being able to extend much further than an adjacent room, but the link between two stones has much greater range, at least a few thousand miles. In addition to working on Humans and Ancients, it is also shown to be compatible with the Nakai. Communication stones are inert unless initialized by someone with the Ancient Technology Activation gene or connected to a Long-range communication device. After they are initialized, however, they will link to anyone who makes physical contact, whether or not they have the gene. This link remains until someone new touches the stone, the user dies, or the connection is cleared by some means. Something as simple as grabbing the stone with a cloth will prevent the stone from linking to the person holding it (this may be the method by which the connection is cleared). When used in conjunction with the Long-range communication device, the function of the stones is greatly enhanced. The link to the user will last over much greater ranges, and allows for the person's entire consciousness to be swapped with the person on the other end.
SG-1 found a stone when they traveled to P3R-233. Around the same time, Joe Spencer found one of the stones, where the person who gave to him said that his grandfather had found it in an Egyptian archaeological dig (presumably left behind by the Goa'uld). The devices allowed Spencer and Brigadier General Jack O'Neill to view each others memories, but also caused Spencer to fixate on O'Neill and the events of SG-1, while O'Neill saw the events of Spencer's life — but didn't tell anyone as he found it relaxing.
After a strange device was found in a vault , Dr. Daniel Jackson realized that the stones could interface with the device. He and Vala Mal Doran placed the two stones into the terminal, which transported their minds to another galaxy.
When Icarus Base was attacked in 2381, Colonel Everett Young brought five stones, along with a Federation version of a Long-range communication device, to Destiny. Young was injured during the escape, so Captain Typhuss James Kira used the device to take over the body of Dr. Bill Lee and talk with Lieutenant General Jack O'Neill on Earth, to explain the Icarus personnel's situation. The crew of the Destiny have used them many times since then. Later on, the Nakai manage to find a stone, which Young believes they confiscated from Rush when they captured him (Rush presumably having kept it as some sort of insurance). Rush neither confirms or denies the accusation.
In 2383, Neeva Casol, while stealing artifacts from a village, discovered a series of communication stones and the accompanying communication device. She unwittingly activated the device and switched bodies with Dr. Jennifer Keller, who had touched a communication stone in Janus' lab.