"Passage Rites, and Rights of Passage"
For many years,
the jumpgates had been
a vital part of galactic society,
and along with them,
the shapeshifters had become
a crucial support for the far-flung planets.
Traversing a jumpgate
was not without its risks, and so
people often made it a rite of passage,
or occasionally a dare.
It was generally accepted
that the shapeshifters could go
wherever they need to go --
or more precisely, wherever
they were needed.
Few planets disputed this,
because of the clear advantages
in receiving aid from the shapeshifters.
The Diamante were different from the beginning.
At first, nobody even understood
what they were or how it happened
or why it was so important.
They only noticed that some people
began to appear with a mark,
a star-bright glint of light
caught under their skin,
usually on a hand.
They ignored it
as long as they could,
until it became inescapable.
What people noticed was that,
if a star-jeweled person came on board
the approach to a jumpgate, nobody else
could go through until that person had.
After a considerable amount of research
and nosy questions, it was established that
one of the recently discovered jumpgates
had started marking a few of the people
who traveled through it, and after that,
every other jumpgate treated them
with exceptional respect.
And demanded that everyone else
do likewise, or be marooned.
There were some pert comments
about the resemblance of the mark
both to an archaic wedding ring and to
the "diamond ring" of a jumpgate activating,
but there was no way around the thing.
So the Diamante were recognized
out of necessity, and their jumpgate
became known as the Groomsman Gate
(even though it chose roughly equal sexes),
and it was agreed that this rite of passage
conveyed rights of passage throughout space.
The jumpgates were just glad to have friends again.
* * *
Jumpgates are stationary transit devices which cast passengers far across space.
Rites of passage are important social events marking the life stages. In this setting, some cultures use the jumpgates as part of theirs, usually for puberty, occasionally other things such as marriage.
Diamante can mean diamond, bejewelled, or any sparkly ornament.
The diamond ring effect happens during a total solar eclipse; the effect of activating a jumpgate produces a similar pattern of light with a larger glint on one side. In this case, bioluminescence mimics the diamond on a wedding ring.
Distinguishing marks are often shared among the members of a group. This version is similar to Claimed by the Supernatural or Touched by Vorlons. Note that the issue of consent has some complications, because humans and jumpgates cannot communicate directly nor with any degree of finesse -- until they start finding some workarounds, and the Diamante mark is one of those. People are generally aware that going through a jumpgate is only a request, not a guarantee, and anything could happen; so it's a sort of fuzzy consent, but it's the best they can manage under the circumstances.