In Tibetan Tantric Buddhism, a tertön is a treasure revealer that carries on the Tantric tradition through receiving special terma, or treasures.
He entrusted many teachings to each of them for later dissemination. With their assistance he then concealed these as treasures in various places – rocks, lake, temples, statues, and even in the sky and in the mindstream of the recipient. He then prophesied that, in the future, these disciples would reincarnate, reveal these teachings from their place of concealment and spread them for the sake of beings.
A vast system of transmission lineages developed, particularly in the Nyingma school where scriptures are updated according to terma discoveries.
Often tertöns experience a vision of a being who hands them an inventory of the treasures to be revealed, with the location.
A kind of treasure that is sometimes considered a third stream of transmission is dagnang (dag snang) or pure vision. In pure visions the tertön has a vision of Padmasambhava or another saint from the lineage who transmits the teaching. Two other primary methods of revelation are earth treasure (sa gter), which are physical objects revealed from actual places, and mind treasure (dgongs gter), which are extracted from the mind of the treasure revealer.
In order for the tertön to find the treasures listed in the inventory, many auspicious connections need to be gathered. Often, but not always, one condition is that the tertön meet a predestined spiritual consort through whom his or her spiritual channels will be untied, allowing the free flowing of the teachings through the tertön’s wisdom mind.
Not to be fooled by fraudulent claimants that come forth Padmasambhava cautioned
“hidden enlightened beings appear in uncertain form” and, by contrast, “fool-deceivers are great hypocritical mimics of the dharmic practitioner.”