Rubber; Cork, Acrylic or Wool.

http://www.snopes.com/music/media/marker.htm

 

Green marker around the edges is for CD's.

 

Cork mat underneath the thick rubber mat from a Dual CS505-2 on my Rega Planar 2. Sounds great and no static issues.

 

Pro-ject Acrylic for the Debut III

 

Aluminum.

It's the platter surface of both my B&O 8002 and VPI Classic2 turntables. I've been putting my records on aluminum platters for three decades now.

 

Platter surface. I am leery of using anything that can't be cleaned thoroughly and frequently, not to mention easily. But I also use a clamp. I think that without a clamp the platter surface can be a bit prone to slippage.

 

Another fan of this beautiful deer hide mat. Money well spent and I had it in less than a week. Looks very cool and static is gone. Thick enough to use alone but thin enough to add on top without a major VTA change.