Gem Rummy is like Gin Rummy and uses a Standard 52-card deck, except each card has a background color with a symbol; Kings have two background colors; each group of 8 cards (starting with Aces) includes all 8 gems. (Jokers are included but are not used in hands).
The object is to get your hand down to a few point of Deadwood by getting Melds. There are 3 phases to each hand: 1) Deal & Roll; 2) Card Play; 3) Showdown & Scoring.
Cards in Melds and Lay-offs will not score for your opponent, but have no inherent point values themselves. Cards not in Melds or Lay-offs are called Deadwood and might add point to your opponent's score. There are 4 different Melds available: Sets, Runs, Stashes, and Queen's Diamonds (the latter two are new).
--SET: At least 3 consecutive cards of the same rank (i.e., 5, 5, 5).
--RUN: At least 3 consecutive card in the same suit (i.e., 6, 7, 8, all clubs).
--STASH: At least 4 cards of the same gem color (i.e., 4 Emeralds).
--QUEEN'S DIAMONDS: Any one Queen + one designated Diamond card that is determined by the initial roll number on the dice. Both dice are added to find one number (i.e., 3 and 4 = 7, indicating a 7 of diamonds is the card). An "11" or "12" indicates the Jack of diamonds.
Refer to these four definitions as you read through the rules:
-Deadwood -- a player's card value total that is not in Melds or Laid-off cards; the card values may count against that player when differencing total values to determine points (i.e., a player has a 3 of clubs and 7 of diamonds left as Deadwood, so her Deadwood total is "10"). (Thematically, players may choose to refer to Deadwood as "Rough Cuts").
-Laid-off cards -- a player's own cards laid down during Showdown that can extend and opponent's Melds but not their own Melds. Laid-off cards do not count as Deadwood.
-Knock -- when someone has equal to or less Deadwood total card value in their hand than the number shown on the dice, that person may "knock on the table" and cause a Showdown of cards; that person is then the Knocker and the opponent is the Non-knocker.
-Showdown -- this occurs once someone has "Knocked", then players will lay out their cards showing their Melds, Deadwood, and Laid-off cards; Scoring then occurs.
1) Deal & Roll: Randomly select a dealer who deals 11 cards to each player while the non-dealer rolls two 6-sided dice to determine the Knock maximum number/Diamond number; put the rolled dice on the Red Joker. The other cards are set in a face down draw deck, then one is flipped face up to the side of the deck (discard pile); the non-dealer has the option to take the face up card. If she does not, then the dealer has the option. If neither player wants it, the non-dealer takes the top deck card and starts play; the winner of a hand deals the next hand.
2) Card Play: Keeping their cards secret, each player takes turns drawing into their hand either the top face up discard or the next draw deck card, then discards any one cards from their hand face up to the discard pile. In a 2-player game, only the top discard card should be visible/accessible. When a player has non-melded cards in his hand equal to or less than the number shown on the dice (2 - 12) that player may decide to "Knock" on the table -- if they do, this means the hand is over and players will start the "Showdown & Scoring".
3) Showdown & Scoring: Players lay our all of their cards on the table in the Melds described earlier, and put their Deadwood to the side. The Non-knocker then lays off any cards on the Knocker's Melds that he can. King is high; Ace is low (no wrap-around). Value for Face cards = 10; Aces = 1, all other cards are worth their printed value.
There are 5 bonuses that can be earned during scoring: a) GIN; b) BIG GIN; c) UNDERCUT; d) GEM PARTS; and e) MINIMUM SCORE of 11 POINTS.
GIN and BIG GIN (Knocker only): If a player can manage to "Knock" at the end of their turn after discarding a card, while having no Deadwood cards in hand (all 11 cards in Melds) she can call "GIN" and score a bonus of +25 points. If a player can do the same above but also avoid discarding a card (have all 12 cards in Melds) she can call "BIG GIN" and score a bonus of +35 total. Opponents cannot lay-off cards on GIN and BIG GIN hands.
UNDERCUT (Non-knocker only): If the Knocker claims a Deadwood number that the Non-knocker can equal or get lower than, after laying down Melds and Laid-off cards, the Non-knocker may claim UNDERCUT for a +25 point bonus.
GEM PARTS (All players): If a player has all 8 different gem cards anywhere in their hand in Melds, Deadwood, and/or their own Laid-off cards, during Showdown he may claim GEM PARTS. Cards used in GEM PARTS only, but not in a Meld or a Laid-off card, still count towards Deadwood. If the Non-knocker has GEM PARTS, she scores +8 points, and if the Knocker has it, he scores +16 points. Kings may only count as one of their two gems for the GEM PARTS bonus; Kings that occur in a STASH may use their non-stash color to help get GEM PARTS.
MINIMUM SCORE of 11 POINTS (Knocker only): If the Knocker is not Undercut, and did not score GIN, BIG GIN, or GEM PARTS, and also fails to score a total of at least 11 points from the Deadwood difference, she scores a minimum of 11 points. If she is Undercut, she is not eligible for this minimum (in 3-player game this is only true if Undercut by both opponents).
--When at least one player reaches or passes 110 total points at the end of a hand, the last hand has been played; the game winner is the highest total score after scoring this hand.
--The Knocker may never lay-off his cards on the opponent's Melds.
--No Melds may be split up once established, and each card may only be used in one Meld.
--At the start of a player's turn, if there are only two cards left in the draw pile, the hand is "drawn" and no score or win is awarded; the same player who just dealt deals again and the Knock/Diamond number is re-rolled.