Small hard points on spark plug porcelain shards make it simple for them to locate a glass breaking point. They can also be used to smash a car’s side glass. Spark plug porcelain pieces are sometimes called ninja rocks because of how easily they can shatter glass.
Aluminum oxide ceramic, which is used to make spark plugs, is very hard. The shard’s impact on the glass causes a microscopic structural flaw, which quickly distributes the tension and breaks the rest of the screen. Spark plug fragments are useful, but they don’t always work.
Spark plug pieces may not shatter glass if they are not sufficiently sharp or are launched with insufficient force. Spark plug porcelain shards have a unique lamination property that strengthens their resistance to impact, making them less effective on windshields.
Spark plug shards that have broken off are regarded as weapons in several states. This is due to the fact that thieves occasionally use them to break into cars. Carrying spark plug chips or bits is a crime in the state of California. Carrying spark plug chips might result in a $1,000 fine or a 6-month jail sentence, depending on the person.