K.1.1- Cards of type Artifact and Artifact Creature are considered artifact cards while in or out of play. They are considered "artifacts" only while in play. While on the stack they are artifact spells. [CompRules 2001/07/23 - 214.3]
K.1.2- A permanent in play may become an artifact due to the effect of a spell or ability. Turning a permanent into an artifact does not change the color of that permanent to "colorless". The permanent keeps its color. [D'Angelo 1998/02/03]
K.1.3- When an artifact spell resolves, it is put into play as the last part of the resolution. [CompRules 1999/04/23]
K.1.Ruling.1- Artifacts typically have no color due to the fact that their mana cost includes no colored mana, but they can be given a color by a spell or ability. [CompRules 2001/07/23 - 214.6a]
K.1.Ruling.2- On some really old cards (from Limited Edition, Unlimited Edition, Arabian Nights, and Antiquities), the terms "Mono Artifact", "Poly Artifact", and "Continuous Artifact" appeared on cards. All such cards have errata. See the individual card entries for details. [D'Angelo 1998/02/03]
K.1.Ruling.3- When an artifact leaves play, any continuous effects it had stop affecting the game immediately, but any duration effects it had last. For example, when Kormus Bell leaves play, Swamps in play stop being creatures, but when a Baton of Morale leaves play, the banding effect continues until end of turn. [D'Angelo 1998/02/03]
Note- Artifact spells can be played only during either of your main phases and only when the stack is empty. See Rule T.2 and Rule P.8.3.
Note- In previous editions there was a rule that when an artifact is tapped, its abilities did not work. This rule no longer exists. Tapped artifacts still have their abilities function. [D'Angelo 1999/05/01] The following artifacts still turn off (due to errata on these cards): Howling Mine, Static Orb, Storage Matrix, and Winter Orb. The following artifacts have one ability that turns off but others that remain working: Voodoo Doll and Watchdog.