An interesting and often ignored episode of the Greek mythology is the one where the ship Argo, built to lead the Argonauts to the conquest of the Golden Fleece, passes through the Symplegades, the clashing rocks. The characteristic of these rocks was to clash each other when someone or something tried to pass between them, killing or destroying everything in their grip.
The Argonauts freed a dove to let her pass through the rocks and, while these retreated after having clashed among themselves to kill the bird, they made readily and quickly pass their ship in the space that for a short time would have separated them. They came out unscathed, except for the aplustre – an ornamental accessory made of wood, placed at the stern of a Greek or Roman ship, where was believed to reside its spirit/life essence – destroyed by the following clash of the Symplegades.
Mostly in fairy tales, but also in the myths, the difficulty in passing through a door or other type of passages (as well as being swallowed by a monster) are images that represent the entry in the realm of the dead (the grave/burial mound). The same is the case with the Symplegades, which symbolize the border with Hades (i.e. the burial mound). They are simply another version of the various animal jaws that hinder the passage, of the doors with sharp teeth, of the slamming doors, of the doors that bite and of the propelled mountains that threaten and impede the entry to a certain place: all are typical motifs found in traditional fairy tales around the world. The opening and the closing, the crushing and the bite all fall in the same custody function.
In any case, remember that only the dead could have free access to the realm of death: you had to be one of them to gain access to that place. This is the reason why the ship Argo loses the aplustre, the part corresponding to the spirit/life essence: in this way the ship “died” and gained the right to enter the grave/realm of death.
The realm of the dead:
Finally the Argonauts arrived in Colchis (the grave/burial mound), where Jason has to accomplish the initiation ritual: there are the challenges to overcome, the sorceress/priestess that helps him (Medea), the snake/dragon and the Golden Fleece hanging from an oak.
Gold is often present in fairy tales and in myths, always connected with events that take place in the realm of the dead/burial mound. Some examples are the Golden Bough of Aeneas, the Golden Apples of the Hesperides and the Golden Horns of the Hind (in the mythologies and foklore of Europe the deer [deer’s antlers were used in the Stone Age to dig the entrance of the graves/burial mounds], the reindeer [like the reindeer that pull the sleigh of Father Christmas], the horse, the swan and the goose [both are migratory birds associated with waters, i.e. the amniotic fluid: the migration is a periodic and regular movement linked to the alternation of the seasons and associated with the cycles of death and rebirth] are psychopomps animals in the context of initiation rituals: they reveal the path that leads to the realm of death) during the labors of Heracles, and obviously the Golden Fleece.
In all these cases it is not the object itself that matters, but gold itself, connected to the dead and to the grave as it is an element that never oxidizes with the passage of time, therefore being a symbol of immortality/eternal life, a solar and regal symbol, in the context of rebirth of the memory and knowledge of the ancestor in the grave, reincarnated into one of his descendants. The hero must obtain the golden object in order to conclude his task and return from the place where he found it, just like the child who had to face the initiation was tasked to obtain (in more recent times, compared to the primordial structure of this ritual) the treasures made of gold inside the grave of the ancestor, to accomplish the rebirth and successfully return from the burial mound!