There are many types of polishes on the market that work in rock tumblers and other lapidary equipment. Deciding what one to use can be confusing. Here are some basic tips on picking the right polish for the your rocks.
Aluminum Oxide Polish. This is a common rock polish that works well on hard "silica" type rocks like agate, petrified wood, and jasper. It is generally the cheapest polish, which is why it is the polish of choice for most beginning rock tumbler kits. Sometimes you'll find Tripoli or red rouge in rock tumbler kits. Tripoli and red rouge are not rock polish. Read about them below. Aluminum is fine for the beginner, unless there is a special need.
Cerium Oxide Polish. This is a medium grade polish that works well on all types of agate, quartz crystals, petrified wood, jasper, feldspar, and obsidian.
Tin Oxide Polish is the best. This high grade polish works well on everything. It will put a great polish on all the hard materials such as agate and even the harder stones like corundum (rubies and sapphires) as well as softer stone like glass and obsidian. This is my pick! If you want the glass-like shine use Tin Oxide.
Linde A ( or "B" or "C") Polish. This is facet grade polish and even though it works on agates, it is cost prohibitive. It is generally used only to facet gemstones.
Polishes to avoid…
Some companies package Tripoli & Red Rouge as rock polish. These materials are designed for polishing metals (which are much softer than stones) and will not do anything to polish the rocks. They are abrasives contained in a wax. When you use them as polish you are only putting a wax on your stones that will wear off rapidly leaving you with a non-polished stone.
Fabuluster, Lusterite, Luster-Rite, and many of the other trade name polishes are usually just other names for aluminum oxide. Buying it generically will save you money.