The Golden Crane signet ring is the ring worn by Malkieri kings. Nynaeve al'Meara describes the ring as "a signet ring, heavy gold and worn with age, almost large enough for both her thumbs to fit through. On it, a crane flew above a lance and crown, all carefully wrought in detail."
When al'Lan Mandragoran was evacuated from Malkier in 953 NE, he was given four gifts from his parents, al'Akir and el'Leanna; an oath sworn in his name, the sword of Malkieri kings, a locket with paintings of his parents, and the Golden Crane signet ring. He had carried the ring ever since, holding to his heritage while denying his kingship, until he found a reason to part with it.
Over forty years later, Lan met Nynaeve. While he refused her timid advances, he was eventually overcome. Calling her mashiara, meaning "lost love" in the Old Tongue, Lan gives Nynaeve his ring, saying "Show that, and you will have guestright, and help if you need it, from any lord in the Borderlands. Show it to a Warder, and he will give aid, or carry a message to me. Send it to me, or a message marked with it, and I will come to you, without delay and without fail. This I swear." Nynaeve has since carried the ring on a thin gold chain, and at other times a leather cord, around her neck.
The ring has been recognized a number of times, although not in the way Lan had mentioned. A Myrddraal once saw the ring and knew that Nynaeve, along with Elayne Trakand and Egwene al'Vere, were the right women to have been captured by several bandits. Shortly thereafter, Rhuarc, clan chief of the Taardad Aiel also recognized the ring..
In 1000 NE, the ring was used as Lan intended. After Nyneave left Lan at World's End, she Traveled to The Queen's Lance in Kayacun. There, she shows Weilin Aldragoran the ring. The Malkieri merchant sees both the ring and Nynaeve's ki'sain and swears that Lan will not ride to Tarwin's Gap alone.