Finder Compass Mod 1.8.8/1.7.10/1.7.2

Description

What this mod does:

Diamonds within a certain range and in your height region appear on your standard compass. If there are multiple, it always points to the closest one. It will by default _not_ point to diamonds "above the ceiling" or "below the floor". If you really want to clean out an area, you have to run through it in different heights. For performance reasons any scanning only occurs once a second. Scanning is multithreaded and should not lag your Minecraft.
Dungeon Finding Needle. Unlike the Diamond Scan, this will only run every 15 seconds. Also different: It checks a lot more space below and above you. The green Needle will then point you toward the coordinates of the Mob Spawner inside the dungeon. Once you are at the coordinates (but wrong height), the needle will point up or down, indicating whether the dungeon is above or below you. Note Dungeons and Strongholds are so rare you might just not be in range of one.

How to install:

Download link
Finder Compass Mod 1.8.8/1.7.10/1.7.2