The Amethyst , a purple gem. Its a fairly common gem found in caves which emits a small amount of dim light for a few blocks.
The Amethyst is used to craft:
-The Amethyst Upgrade at the Portal (1 Amethyst, 20 Time Crystals)
-Amethyst Pickaxe (5 Amethysts, 20 Time Crystals)
-Amethyst Chandelier (5 Glass, 10 Amethysts)
Amethysts are fairly common and can easily be found in a cave. They appear to be floating when first seen and when picked, it will make a loud chime noise. Amethysts can also be obtained by using a gold pickaxe on rocks, such as Stone and Limestone.It is very valuable but not as valuable as a gold coin.