Don't they have some other purpose?Go ore hunting. Selling your ores nets you the most rupees, and it's pretty easy to find a bunch just exploring the world.
They do, but you'll have a surplus if you just mine when you see them. More than you'll ever need.Don't they have some other purpose?
Go to Pondo's Lodge in Hebra and play his snowball bowling mini-game. It only costs 20 Rupees, and getting a strike on the pins earns 300 Rupees. 4 strikes and you have 1,000 and it can take as little as 5 minutes if you know the trick on where to stand to consistently get a strike. Here is a video of me doing it:
Besides the bowling game there's another way to make a huge lot of money fast, like REALLY fast.
Needed: a fireblade, arrows, gear to prevent you from getting harmed.
Where: faron spring because faron appears right in front of your nose.
There's already some flint on the ground so you only need to burn it. Wait by the fire and choose wait till morning. As soon as the cutscene is over get your bow and arrows ready and make sure you wear the proper equipement. Now let the draft take you and aim. Hit the dragon. Of course the horn is more valuable but if you don't hit that one anything else is fine. Land and don't collect your treasure yet. Sit down by the fire and wait till morning again. Repeat the whole shooting thing. The dragon scales, horns, claws and teeth won't vanish if you sit by the fire and wait till morning. After doing this for a while collect your prizes and go to any seller and sell your dragon items. This will give you a lot of money in a very short time