I was doing some internet surfing the other day, and realized that there are now 8 Infinity Stones (I think they're called Infinity Gems in the comics): Power, Space, Mind, Soul, Reality, Time, Death, and Continuity. Now, I know about the first six (Power, Space, Mind, Soul, Reality, & Time) due to the movies in the Marvel Cinematic Universe (MCU). However, I don't know much about the Death Gem and all I know about the Continuity Gem is that it was apparently revealed in a Deadpool book.
Can someone explain to me what these two Gems are and what they do, their purpose?