So you don't break quartz, redstone, diamond, lapis, emerald, or ruby. Of course there's coal as well. Anything that can be fortuned for more or can be pulverized for more you want to silk touch while out mining to save space in your miner's backpack. Also, for nether ores you want to silk touch them so they don't explode.
As for building hammers, the head determines mining level, speed, and base durability, the plates determine speed and base durability, and the rod determines the durability modifier. What this means is an all stone tool won't have as much dur as a tool with a wooden handle. If you look at the bonuses in materials in me you can see what you want. For example if you can get it, until many handles green slime handles have the best dur mod, but using them as a plate will slow down your mining speed drastically. This is why I suggest a wooden handle, stone head, and two flint plates for a starter hammer - the flint plates will boost the speed of the hammer since flint is faster than stone for mining, and it will increase the dur somewhat since it has a higher base dur.
The reason I wouldn't want to go with an all iron tool, for example, is the hammers can get expensive to repair really quickly, so you'll want your "good" hammer to at least have a slime handle and massive dur. This is why I like the idea of getting steel asap since it can replace alumite for your nether mining needs, has high dur, and has high speed. Once you can make steel it's easily replaced as well.
(ive found like 15 emeralds and no diamonds...)