Resin

Could it have been Inlace? You can get it solid colors as well as with crushed stone. It’s (I think) a polyester or acrylic 2-part resin. It’s pretty easy to work with but stinks to high heaven until it’s cured.

-- Use the fence Luke

there are many types out there. Make sure that the one you get can be sanded smooth

-- making sawdust....

Yes, Probably something like Inlace. I used it on this desk. It comes in many colors. Works sort of like Bondo.

-- Charlie M. "Woodworking - patience = firewood"

Sorry Sac, not in my domain.

-- Grumpy - "Always look on the bright side of life"- Monty Python

I use West System 2-part Epoxy resin. It is used primary for fiberglassing, like the hulls of canoes and kayaks. I also it on the rocker to leg joints on the chairs. This is a light-colored resin though and will be transparent when cured. I believe you can get tints and dyes to mix any color you want, but I have not experimented with this.

I have never used it as a filler like you are talking about. It has to be built up in many layers to prevent cracking and excess air bubbles, my first fish tank build and I thought it would be cool to do corner pours, so I set up the tank at 45 degree angle, made sure it was level and poured enough in there til it was 3/4” deep, big mistake, there were so many cracks during the curing process that it leaked and eventually I had to cut it all apart and start from scratch.

-- Rich, WNY, www.nyrockingchairs.com