I've lost one of my lug nuts and need to buy a new one tomorrow, going to a big car show tomorrow night so i'm pretty desperate.
The first thing i

 

Just take another lugnut off another wheel and match it at the shop you plan to buy from. You'll need the proper thread pitch, taper angle, length, width and overall size (for the lug wrench). This way, there will be no mistake.

 

12x1.5 if i am not mistaken

-seat shape(cone, round, flat)

-19mm is the stock outside size

-material and finish(titanium, forged aluminium, chrome plated steel, etc)