206.1 The expansion symbol indicates which Magic set a card is from. It’s a small icon normally printed below the right edge of the illustration. It has no effect on game play.
206.2 The color of the expansion symbol indicates the rarity of the card within its set. A red-orange symbol indicates the card is mythic rare. A gold symbol indicates the card is rare. A silver symbol indicates the card is uncommon. A black or white symbol indicates the card is common or is a basic land. A purple symbol signifies a special rarity; to date, only the Time Spiral™ “timeshifted” cards, which were rarer than that set’s rare cards, have had purple expansion symbols. (Prior to the Exodus™ set, all expansion symbols were black, regardless of rarity. Also, prior to the Sixth Edition core set, with the exception of the Simplified Chinese Fifth Edition core set, Magic core sets didn’t have expansion symbols at all.)
206.3 Previously, a spell or ability that affected cards from a particular set checked for that set’s expansion symbol. These cards have received errata in the Oracle card reference to say they affect cards “with a name originally printed” in a particular set.
206.3a One card (City in a Bottle) refers to permanents and cards with a name originally printed in the Arabian Nights™ expansion. Those names are Abu Ja’far, Aladdin, Aladdin’s Lamp, Aladdin’s Ring, Ali Baba, Ali from Cairo, Army of Allah, Bazaar of Baghdad, Bird Maiden, Bottle of Suleiman, Brass Man, Camel, City in a Bottle, City of Brass, Cuombajj Witches, Cyclone, Dancing Scimitar, Dandân, Desert, Desert Nomads, Desert Twister, Diamond Valley, Drop of Honey, Ebony Horse, Elephant Graveyard, El-Hajjâj, Erg Raiders, Erhnam Djinn, Eye for an Eye, Fishliver Oil, Flying Carpet, Flying Men, Ghazbán Ogre, Giant Tortoise, Guardian Beast, Hasran Ogress, Hurr Jackal, Ifh-Biff Efreet, Island Fish Jasconius, Island of Wak-Wak, Jandor’s Ring, Jandor’s Saddlebags, Jeweled Bird, Jihad, Junún Efreet, Juzám Djinn, Khabál Ghoul, King Suleiman, Kird Ape, Library of Alexandria, Magnetic Mountain, Merchant Ship, Metamorphosis, Mijae Djinn, Moorish Cavalry, Nafs Asp, Oasis, Old Man of the Sea, Oubliette, Piety, Pyramids, Repentant Blacksmith, Ring of Ma’rûf, Rukh Egg, Sandals of Abdallah, Sandstorm, Serendib Djinn, Serendib Efreet, Shahrazad, Sindbad, Singing Tree, Sorceress Queen, Stone-Throwing Devils, Unstable Mutation, War Elephant, Wyluli Wolf, and Ydwen Efreet.
206.4 Players may include cards from any printing in their constructed decks if those cards appear in sets allowed in that format (or those cards are specifically allowed by the Magic: The Gathering Tournament Rules). See the Magic: The Gathering Tournament Rules for the current definitions of the constructed formats (WPN.Wizards.com/en/rules-documents).
206.5 The full list of expansions and expansion symbols can be found in the Card Set Archive section of the Magic website (Magic.Wizards.com/en/products/card-set-archive).