|Introduced||August 10, 2015|
|Rare Gem type||Limited|
When the player begins a game with Sunstone activated, a random number of unique yellow gems that resemble eight-pointed stars will drop alongside the other gems into the board. A star, when cleared from the board, explodes, destroying itself plus the eight surrounding gems as well as gems in the cardinal and both diagonal directions in a 7×7 area. The base value for clearing a star is 600 points. While Sunstone is active, stars will replace random yellow gems throughout the game (except during the Last Hurrah and optional Encore), and Flame Gems created using yellow gems will result in creating stars instead.
After the Last Hurrah (or Encore if the player accepted Feathered Fury's offer), a Coin bonus occurs in which nine star icons appear in a 3×3 arrangement. When the player selects an icon, it reveals a numerical Coin value that is then added to the player's Coin total. The Coin payouts the bonus offers are 1,000, 3,000, 6,000, 10,000, 20,000, 50,000, 75,000, 100,000, and 200,000.
- The name of this Rare Gem is a pun on sunstone, a chatoyant gem consisting of feldspar.
- Although Sunstone is a limited Rare Gem, its harvest screen is missing the "LIMITED TIME ONLY" tag.