DeSean Jackson -- I'm Wearing Your Salary On My Neck ... If You Make $75K A Year

Note to all district attorneys*, hydrologists*, and physical therapists* ... TMZ Sports has pics of what 12 months of your salary ($75,000) looks like around the neck of NFL star DeSean Jackson.

DeSean -- whose Redskins are 3-7 -- decided to cheer himself up with a "Treat. Yo. Self" moment ... and hooked himself up with a monster chain from one of L.A.'s top jewelers.

How monster you ask? 2,200 diamonds, 22 inches and a HALF KILO of gold. Treat. Yo. Self.

The Dr. Frankenstein behind the bling is Ofer -- Ceo of NuO jewelry in L.A. He tells us DeSean wanted a Cuban link chain ... which is back in style these days thanks to stars like Jay Z and Usher.

He ordered one in pure gold, but when he got it back ... DJ decided it wasn't quite swaggy enough so he put in another work order with Ofer that involved more ice than the North Pole.

Ofer tells us Desean's customizations pushed the value of the chain to $75,000. Easily one of his most expensive pieces ever.

Treat. Yo. Self.