Cobaltoan Calcite
The first mineral you will explore is Cobaltoan Calcite. It introduces you to minerals in general, and particularly this one, with low Mohs hardness.
Amethyst
Next on your list is Amethyst. You will learn about Amethyst and Bismuth both on this page!
Alexandrite
The last on the list is the Alexandrite and Wulfenite page. You will enjoy many a pun on this page; I really killed it on this particular page.