Green Coin

Green Coins are a variety of coins that first appear in New Super Mario Bros. U.

New Super Mario Bros. U / New Super Luigi U / New Super Mario Bros. U Deluxe
Green Coins appear in New Super Mario Bros. U, New Super Luigi U, and New Super Mario Bros. U Deluxe. After going through a Green Ring, it spawns one group of three Green Coins appearing at a time while rotating clockwise in a pattern of a three-leaf clover (with the coins still spinning). But they appear for less time, disappearing in three seconds if all of them aren't collected in time. The timer resets when next group starts appearing in a different spot after the previous group is collected. Only five groups of three Green Coins are collected to clear, with a total of fifteen individually. When a Green Coin is collected, a green numbered text appears based on the corresponding amount collected. The effect they have is very similar to that to Red Coins, as collecting all of them gives the player a power-up or 1-Up Mushroom. They use the same sound as yellow coins if only one or two of them in a group are collected, but collecting all three of them uses the same sound effect as collecting a red coin while making incrementing sounds with each group collected and a green numbered text appearing after each amount is collected. Green Coins are worth a yellow coin.

Super Mario 3D World
Green Coins reappear in Super Mario 3D World. This time, resembling as small Star Coins. After going through a star-shaped Green Ring, eight Green Coins start to appear separately like red coins. But they only appear for a limited-time and will disappear if they aren't all collected in time, but if the player collects them all within the time limit, a Green Star appears on the same spot where the last Green Coin was collected. When a Green Coin is collected, a dark-green numbered text appears based on the corresponding amount collected. They also make a distinct sparkly sound when collected while incrementing sounds with each one collected. Green Coins are once again worth a yellow coin and one hundred points. They are also referred to as Green Star Coins in the Prima Games guide.

Trivia

 * In Super Mario RPG: Legend of the Seven Stars, the Frog Coins in-game sprite appear as regular coins with a green palette due to limitations.
 * In the Peach's Castle tech demo for the Nintendo GameCube, when entering the room "How Many Coins?", green coins can be seen among the many colored coins that fly out of the ? Block after hitting it.
 * Green Coins are unused in New Super Mario Bros. Wii, having a leftover model and texture and apparently replaced by Toad balloons.
 * Despite their name, Black Coins have a dark pine green coloration.