A gold or yellow bell with a red line through it, which is commonly used on mobile phones as an icon for the silencing of notifications or ringing sounds. A mute, or silent mode.
Bell with Slash was approved as part of Unicode 6.0 in 2010 under the name “Bell with Cancellation Stroke” and added to Emoji 1.0 in 2015.
U+1F515
? Bell with cancellation stroke