Which items can be found using an item finder?Also how to use,need equip it or something?

Anyone can answer me , give me a guide tutorial or something?Does it worth the price?

According to other forum posts, you have to equip it under equip items in your inventory, then wander around a map when the weather is sunny, and it finds nuggets, sapphires, rubies, shards, berries, and pearls.

I am in the process of making a map guide, which will be hopefully completed soon :P

For your answer -
Itemfinder can be bought from Dept Store

To use it, go to Manage Items, then go to Equip Items, and there you will be able to equip it.

After that, go to maps and move around like you do and catch some pokemon.Sometimes, you will find an item. The text will be "your itemfinder detected a "item name here".

Itemfinder depends on weather of the city you are in, so it will be easier if you buy a dowsing machine instead.
Itemfinder works best in Sunny or Sunshine or Summer weather (At least thats what I have found)

You can get shards, berries, sapphires, nuggets, rubies, balm mushroom, pearls etc.