Why tin oxide?

Why tin oxide for polishing marble, instead of much cheaper aluminum
oxide, or maybe zinc oxide?

And, do you have a favourite supplier for purchasing it?

Why tin oxide for polishing marble, instead of much cheaper
aluminum oxide, or maybe zinc oxide? 

I can’t speak for marble because I’ve never polished it. I use Tin
Oxide because it will polish about any stone. I use Tin Oxide on
split cowhide or in Vibratory tumbler polishing.

And, do you have a favourite supplier for purchasing it?

Arrowhead Lapidary supply http://www.arrowheadlapidarysupply.com
Kingsley North http://kingsleynorth.com

Rick Copeland
Silversmith and Lapidary Artisan
Rocky Mountain Wonders
Colorado Springs, Colorado
rockymountainwonders.com