Green gem

The Green Gem is a rare type of gem in the Crash Bandicoot series. It's known to be an emerald. Along with the other colored gems, this gem is very powerful and opens up secret areas.

Crash Bandicoot
In the original Crash game, where the colored gems were earned on the same way as the clear gems, the Green Gem is obtained by breaking all the boxes in The Lost City. It opens up the Green Gem Paths in Jungle Rollers and Castle Machinery.

Crash Bandicoot 2: Cortex Strikes Back
The Green Gem appears a bit flat and oblong. In this game, it can be obtained in The Eel Deal by completing the secret course behind a fake wall. It opens up the Green Gem Route in Ruination and part of the Multicolor Gem Route in Spaced Out.

Crash Bandicoot 3: Warped
The sprite of the Green Gem is exactly the same as in Crash 2. It can be obtained by completing the Death Route in Flaming Passion. It opens up the Green Gem Route in Gone Tomorrow and part of the Multicolor Gem Route in Bug Lite.

Crash Bash
The gems awarded in Crash Bash are all green. Each minigame contains a green gem and it can be won by winning a harder version of this minigame. It takes 25 gems unlock the level Keg Kaboom.

Crash Bandicoot: The Wrath Of Cortex
The Green Gem gets a different sprite. The gem becomes more clear. It can be obtained by completing the Death Route in Wizards and Lizards. It opens up the Green Gem Route in Cortex Vortex.