Now that I think about it… a magma bomb does make sense.
Earth mages tend to have an ability that is basically rock throw.
Fire mages tend to have fire balls, which are basically compressed balls of fire that explode on impact.
The combination of both isn’t all that unusual if you take those two facts into consideration. Although it would not result in incineration. Mostly acting as a hand grenade with the fire acting as the detonation and rock acting as shrapnel that would slam into people. Unless you fill it with actual magma in which case the explosion would cause lava/magma to fly all over the place. Considerably more effective and painful than rock.
That or a glass bomb. Imagine a giant ball of glass being smashed into you and then exploding into thousands of pieces of glass shards most of which are flung into your body. That would either instantly kill an unarmoured opponent or cause enough damage for them to bleed out shortly after.
The entire front (or whatever part the glass ball collides with) part of your body will be covered in glass shards that penetrate your skin, puncturing all of your organs including your brain via entry from the eye sockets.
Sounds like a very evil spell combo.
EDIT:
Heck a glass bomb would even make for an amazing room clear. Put it in the middle of all your opponents then detonate it, all of them will get an equal amount of glass shards to the body. The most awesome thing with this is that glass shards are sharper than a medical scalpel since it’s even sharp on an atomic level (as in the atoms are arranged in a way perfect for cutting.).
It’s why obsidian swords are really fucking sharp, but fragile. Yet no one cares when fighting an unarmoured opponent cause they will be horribly injured after the first strike anyways.
Well you could use a catalyst to focus your element into the form you want, like a collapsing rod or staff for a scythe, spear, hammer etc., a cord of some sort for whips, or you could use a knife or something like it to make the base for a sword. Its a possibility any way. Its a good idea too.
@Sakura-chan There’s nothing wrong with the idea Using your ability with a weapon might well be an option - I just don’t want to promise something I might not deliver
A glass bomb from your explanation sounds like a barbed arrow. They’re not made to subdue or kill, they’re made to suffer. Once a barbed arrow is wedged into your flesh its very very difficult to remove, attempting to remove it or even any sudden movements reopens the wound and causes excessive bleeding and pain. The glass bomb sounds like something very similar.
Agreed, the glass bomb is an evil combination.
@AJ_ there’s a good combination for an evil elemental if I’ve ever seen one
Well 1 glass shard sounds like a barbed arrow. Sadly for the person being hit by the glass bomb they will have a lot more than 1 glass shard to deal with. Seriously now I’m hyped for glass magic. It may be half as good as punching people in the face. Or Necromancy.
That reminds me will necromancy be a thing? We all know necromancy is best magic. Not really an element then again “Death” is considered an element in some games.
Yeah but imagine in battle, who would really see if it is glass or not, someone may just bash it with stones thinking it’s just another fireball, but that person would be waiting for a horrible, horrible surprise!
Edit:one more question, are we an elementalist?
Earth Mage: Hah a fireball? Not very creative are we. The Earth mage lifts a boulder and throws it at the incoming ball of fire, to his surprise his rock collides with seemingly nothing. Then that nothingness starts to crack and shatter quickly exploding in a rain of fire, glass shards and molten glass. Only one thing was on the mages mind in his final moments.
Earth Mage: Ah fuck.
PS: @Nathan_Faxon I noticed how when we get deep into a conversation we tend to end up at a very interesting conclusion. I mean by Cthulhu why haven’t I heard of glass bombs yet?! I can’t have been the first person to think that it would be an awesome idea!
We’ve had these conversations on several topics already and we came up with such great ideas as a result. We should have these more often! And glass bombs is definitely a thing that should happen, it’s freakin’ lethal.
@PhoenixReborn I believe the glass bomb will be possible to dodge but it’s a very damaging design. Each shard will most likely be jagged and the velocity it travels at from the explosion will embed itself deep in the flesh, making it difficult to remove without causing further damage and the longer it’s in there the more pain it causes. So you can dodge the majority of it but a single hits you and you’re in for a world of agony, your evasiveness would have to be near perfect.
Yeah, Imagine someone being hit with it in real life, I read this online:there was a explosion in a factory in 1920s and glass shards traveled for 2 miles!
Don’t forget the fact that it’s glass. The longer its inside you the higher the chance it breaks into more pieces, into very small pieces that will most likely stay within you till you die if you survive.
If you try to take out the glass you could easily break it. Causing more pain, injury and more shards that are harder to extract. It’s a spell designed to do massive damage to unarmoured or lightly armoured foes.
It would even work against knights in full armor since shards small enough would hit the face through the visor and breaths. That or shatter against it thus giving your eyes a rain of tiny sharp pieces of glass. As you can imagine tons of pain + blindness.
Also the core of the glass bomb would be incredibly hot, probably have molten/liquid glass that would ALSO fly at the opponent. Causing burns on top of being shred.
Using your ability with a weapon might well be an option - I just don’t want to promise something I might not deliver 
spoilers 