Toughness is what determines energy before breaking and note that while many ceramics are not at all tough, high end technical ceramics are tougher than most metals[1]. High quality WC is indeed tougher than steels. It's also twice as strong as most steel, but high-end steels surpass it in strength.
[1]: http://www.cam.ac.uk/sites/www.cam.ac.uk/files/news/research...
With ceramics and glass, things get a little tricky. You can take a relatively weak and softer piece of pottery ceramic and obliterate the hardened bullet-resistant windows on police cars (the laminate inbetween being a different matter, but the glass itself will shatter/crack.) That happens via ultrasonic frequencies created on impact.
All of that is wrong. You can't use pottery shards or even hard pebbles to break glass; you need very hard technical ceramics[1]. Spark plug ceramic is alumina which is extremely hard.
It has nothing to do with ultrasonic frequencies, it's caused by crack propagation. Tempered glass is under internal stress due to its quench rate and chemical treatment, so as soon as the outer shell is broken the entire thing shatters. Alumina is so hard that a corner can chip off a bit of glass, releasing that pressure.
Ceramics can't be tempered like glass, and like untempered glass they only shatter if an impact by a much harder object is above the fracture propagation energy. That means that most of the time the impact energy is about the same as the actual toughness of the material. For high toughness ceramics there are no materials hard enough to cause chipping, so they break exclusively under normal toughness.
Plenty of pottery contains aluminum oxide, which is very hard.
Alumina will effortlessly scratch gorilla glass, any metal, tungsten carbide and even a lot of sapphire glass. No kind of pottery will do any of those things.
Coal dust will abrade and destroy almost everything and it's because of the graphite, not the diamond. I have a coal mine. It's killed two phones and a drone already.
"Alumina will effortlessly scratch gorilla glass, any metal, tungsten carbide and even a lot of sapphire glass. No kind of pottery will do any of those things."
This is entirely untrue, it depends on the composition of the clay used in making the ceramic, which will be entirely dependent upon the location the clay or clay mix is obtained from. I also happen to do lapidary and pottery work, as a profession (next to LED lighting applications.) You can get clay from Mt. Baldy, make pottery, fire it up, it will scratch the hell out of almost everything because of the sand grain-sized rubies contained within.
if you ever get into trouble it'll be your finger that comes off, not it.
Not really. It's a ceramic and as such will shatter if knocked against another ceramic, hardness notwithstanding. Also, for some reason, my skin eats away at it.
See my tungsten carbide ring vs my fiance's ring (mine is on the left) - both made before the requirement that the rings come with break points built-in - https://i.imgur.com/fSIOUJf.jpg
Note the differences - his ring looks brand new. Both rings bought at the same time, same maker, same style.
Mine's practically obliterated.