Common Rocks Reference has a very simple and clean user interface and makes a good first impression. There are three types of rock listed in the reference guide including Igneous, Metamorphic, and Sedimentary. Each of the categories has a list of all the rocks in alphabetical order.
When you tap on any of the rock names, you will see various from different angles along with some information regarding the rock.
Photos are detailed and also include the scale to help you see the finer details of the rock type.
The app also includes a quiz which can help you test your knowledge regarding rocks. There are five levels of difficulty, each with 12 questions. Only Level 1 is unlocked when you begin, and when you score a minimum of ten out of twelve points, you can progress to the next level.
There do seem to be some stability issues present within this app as it crashed a couple of times while I was using it. It's easy enough to go back to the info, however. I hope the developers look into this and fix it in a future update.
Neha has been writing and editing since 2010 and has been reviewing iOS apps since early 2014. She has lived in four different countries and loves having the world at her fingertips thanks to these awesome apps.