Yes those strange objects you find sometimes dropping from mobs. What the hell are the for. Armour ? Nope. They're for weapons upgrades, and there is a whole serious of them

Depending on which one you use, will decide on which weapon you can use it on, and what specials it adds to that weapon.

If anyone has any details, please feel free to post

the Omnis can upgrade every weapons of the Inamorata series.
the Clans can upgrade every weapons of the Sacrosanct series.

Just combine one Grey Glyph of your choice with the weapon.
You will need some Weapon Smithing skill (ask for an engi).

Look at the database to figure out which grey glyph can a weapon receive.
Of course you cant put a Sneak Attack mod on a ranged weapon.
But you cant put Full Auto either on every ranged Sacrosanct weapons.

I'm not sure about that, but the final QL should be slightly higher than the weapon you're upgrading.
The Grey Glyph are only found at QL100.

Go here >> http://aodb.info/search.asp
Then enter the word Sacrosanct or Inamorata in the Name Box.
And press Search.

oh yea and the weaponsmithing ee and qft reqs are insane so make some engie friends

Who drop these gray glyphs? (and location please)

Easier to get them from the rafters under the bridge to the unredeemed temple in Scheol.

Jayhawk

I killed those for a bit 2 months ago.... not a single drop then... Guess FC wasn't ready with them then

The boss in a static dungeon close to redeemed temple in west scheol drops em all the time.
Also drops arbiter gem's as bonus  

Yes there is a cap, for now a QL100 can upgrade a QL165 weapon.
I dunno where is the cap but there is one.