Cuendillar

CWAIN-deh-yar

Cunedillar is a material made using the One Power that is considered unbreakable. Any force directed against it is said to make it only stronger and even balefire will not destroy it (TSR, Ch. 54). The making of it was lost in the Breaking and all examples date from the Age of Legends (TEotW, Ch. 52). There was some knowledge of it during the breaking however, as the Domination Band was made of cuendillar (This passage needs a reference)

It is rare, and discoveries of troves of it have been known to make the finder rich (TDR, Ch. 48). The weave to make it has recently been rediscovered, by Egwene al'Vere, whose natural ability with Earth was no doubt an advantage. It was accomplished by a complex weave of earth into iron, with few Aes Sedai having sufficient strength to perform it well (CoT, Ch. 17; Ch. 30). There was at the time some debate amongst Aes Sedai over making it to raise finances (CoT, Ch. 17). Though considered unbreakable, the seals on the Bore into the Dark One's prison, made of cuendillar, have decayed and broken (TEotW, Ch. 52). It is also known that the True Power can desroy cuendilar (TGS, Ch. 22). The Aes Sedai belive they have a full record of all cuendillar.

Quotes

Everything ever made of heartstone was recorded in the White Tower, and those seven were remembered above all (The Gathering Storm, Chapter 5)..