What is this speck??

Just picked up this lens last week, off someone on the forum.
They clearly said glass was perfect minus some wear marks on the actual body of the lens.

Was looking closer at the lens today and found this:

If you've got a lens pen, see if it'll come off. If not, send it back.

Gently wipe it off!!!! Glass isn't as fragile as people think! Does it wipe off...is it raised....could be stain! Could be divot...give it a feel.

looks like mold to me

Without a clearer picture, it looks like an impact mark to me.

UPDATE: Ok guys.. you got me brave enough to touch it. I wiped my finger with a alcohol rub.. and touched it.. it SMUDGED.. meaning it's.. oil or something? Now there's a big mess of a streak from it..

What to do now??

As said above, lens pen.

Looks like a booger, gently pick it off and roll it between your index finger and thumb, then flick it on the nearest wall or toss it behind the couch.

Or you can just get a micro fiber cloth and some lens cleaning solution and wipe it off .

It's not on the glass? If so use a Q-tip with water or alcohol and remove it.
May just be salt from a drop of sweat.

blackhawk wrote in post #10010201
It's not on the glass? If so use a Q-tip with water or alcohol and remove it.
May just be salt from a drop of sweat.

Yep,,best solution.. After using a q-tip with a little alcohol give the glass a light buff with a soft clean cloth..

Lenses aren't as fragile as many people think..

waynema wrote in post #10010091
looks like mold to me

then you've never seen mold before.

It's water/liquid/condensat​ion/whatever residue. Clean it off and move on.

yogestee wrote in post #10010246
Yep,,best solution.. After using a q-tip with a little alcohol give the glass a light buff with a soft clean cloth..

Lenses aren't as fragile as many people think..

Yeah, you don't want to temp fate, but it's a lot harder than plastic.
I've used a Q-tip backed microfiber cloth to clean the mirror assembly before with no harm...

You don't want to smear it when you clean it as the rear element is hard to clean without disassemble.

plasticmotif wrote in post #10010295
then you've never seen mold before.

It's very rare for mold to form on surfaces exposed to the air.. Mold usually forms on internal elements..

Cool I cleaned it off with a qtip and alcohol. Dried it off with some canned air. Still a few light stains. Going to bring it to the local camera and and have them do a cleaning.