Can a large glass Rupert Drop somehow be manufactured into a useful and effective weapon in medieval warfare, such as a club?

I've developed a society that primarily lives in the desert with sand in abundance. They used this to their advantage, developing a range of glass-based or glass-strengthened weapons. One of these glass-based weapons i am considering is a "Rupert Drop" club, reinforced at the tail end to reduce it's chance of shattering. Would this be possible and if so, would it have to be made or strengthened in a particular way?

  • $\begingroup$ You should have researched medieval glass-making first as that might suggest what is the feasibility of glass-based weapons. $\endgroup$
    – a4android
    May 7, 2019 at 9:07
  • $\begingroup$ How about the Mere as a weapon, used by the Māori of New Zealand its a good fit for your sand people en.wikipedia.org/wiki/Mere_(weapon)#Material_and_manufacture $\endgroup$ May 7, 2019 at 9:27
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    $\begingroup$ Your setup might have a vital flaw: you need fuel to melt sand into glass ... lots of fuel! Where do your desert dwellers get all the trees or coal for their glass industry? And why don't they use it to melt ore into metal instead? $\endgroup$
    – Elmy
    May 7, 2019 at 9:58
  • $\begingroup$ @Elmy They don't have access to such resource, such as metal ore, hence their utilization of sand. As for heating the glass, they have a unique fantasy inspired source of energy. $\endgroup$ May 7, 2019 at 10:13
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    $\begingroup$ I'm surprised you went with "can they be used like a club" rather than "can they be used like a grenade". I doubt glass dust is a healthy thing to breath. $\endgroup$
    – Giter
    May 7, 2019 at 14:28

6 Answers 6


Certainly, all you have to do is remove that vulnerable tail and you're all set. Clipping it off with a pair of pliers should do the trick.

Oh, right.

While the resilience of the head of the drop is legendary, it's only resilient relative to the normal properties of glass rather than being specifically highly resilient. The traditional test is to hit it with a hammer. (You're better off using the hammer if you want a weapon.) If you hit it hard enough from the head, it will still shatter leaving you holding a handful of glass.

There are ways of making glass resilient, but the very specific properties and specific vulnerability of Prince Rupert's drop is not the way to go.

What about toughened glass?

This is a similar concept to Prince Rupert's drop. The glass has a stress structure that gives it its strength, but that structure also gives it a weakness. The outer layer is in compression, and the interior is in tension. While you can batter away at it with your fists to no great effect, anything that damages the surface, such as an automatic centre punch, causes the entire pane to shatter into "safe" chunks. However this would allow you to use it for weapons until such time as your opponents discovered the counter.

  • $\begingroup$ What if the tail end was strengthened somehow. Something that would absorb attacks, keeping the tail end of a rupert drop safe, whilst utilizing it's resilience at the head of the weapon for heavy blows? $\endgroup$ May 7, 2019 at 8:57
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    $\begingroup$ @PopularMisfit, it would cease to be Prince Rupert's drop, it would just be a glass club. The drop is defined by a very specific stress structure such that the whole thing explodes if the tail is damaged, it's that stress structure that gives the head its strength and the tail its vulnerability. $\endgroup$
    – Separatrix
    May 7, 2019 at 9:11
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    $\begingroup$ I believe on of the slow motion channels at YouTube demonstrate that the head of the Prince Rupert's drop can withstand a gunshot without any damage. It does explode after being shot though, but that's because the tail breaks... $\endgroup$ May 7, 2019 at 9:49
  • $\begingroup$ @Spoki0 Yes, i saw those too, most likely due to the vibration. I was wondering if it would be possible to reinforce the tail end with something that would absorb those vibrations so that it could actually be used as a weapon. $\endgroup$ May 7, 2019 at 9:52
  • $\begingroup$ @Spoki0, the first one I found was a high powered rifle which does overwhelm the head. $\endgroup$
    – Separatrix
    May 7, 2019 at 9:57

Rupert Drops specifically... no. While Rupert Drops are surprisingly resilient when hit on the head, the tails are notoriously fragile, and if you break the tip, the head disintegrates. Keeping the fragile tail in tact in a fight is just not going to happen; so, a solid hunk of glass mounted to the end of a stick would likely serve you better.

Now, if you want to know the best way to make a club out of glass, the answer is probably synthetic mother of pearl. Nacre (mother of pearl) is a glass like substance made from a microscopic lattice work instead of solid material. Nacrized glass is 200 times as shatter resistant as solid glass meaning it would hold up to the abuse of a fight just as well as any metallic weapon. Now, this may not be very realistic since a civilization with the technology to make nacrized glass probably is not fighting with clubs, but if you feel comfortable with a little bit of handwavium to say that they figured out how to nacrize glass ahead of modern civilization due to their strong environmental factors, it could make for a cool story.

It would also explain why they aren't just digging a little deeper to get to the actual metal ores under the sand as John pointed out.


there are several problems, but it can be done if they really want to.

  1. If they live in a desert where sand is the only resource, they don't have much use for weapons, especially ones they cannot hunt with. They won't have much of a civilization.

  2. first even sandy deserts only have sand covering a small portion of their surface, and by its very nature the sand is fairly shallow. so they can get to bedrock, thus they have access to stone and metal.

  3. If they have access to the clay and other chemicals needed to make a kiln and purify glass then you have access to metals. There is a reason glass is something people invent late in therms of technology.

  4. If they can grow crops they can grow wood, and wood makes for much better weapons, for one thing you can make bows with it. Your people might use glass instead of metal, but their is no way they can't make a wooden club and a wooden club is more durable than a tempered glass one.

  5. Lastly prince rupert drops are toughened by shape not just material. Prince rupert drops are tough because they are roughly spherical. There is no lever arm unlike a club, make a club of tempered glass and it will shatter when you hit something. tempered glass is not that strong under tension. Worse glass suffers from fatigue, use a glass club repeatedly and in no time you are holding a pile of sand.

If your people are dead set on having one (religious reasons maybe?) it will have to be small, like a stone club which has similar problems. Thankfully they do exist. The mere club of the Maori is solid stone (jade or serpentine usually), it is also only a foot or so long. Note you can't drill your glass club it will shatter. Don't expect them to last very long, they will fatigue faster than than the stone clubs. Of course since they will be cast they will be easier to make than the stone ones so this may be acceptable.

To make them they will have to cast the glass, let it cool, remove it form the mold, then reheat it in a oven and quench, several steps but still faster than carving stone.

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When it breaks it's explodes at 1600 meters per second so yes it can be used as a projectile weapon. The problem is I'm having a hard time figuring out the specific size of the fragments. If the fragments are too small you get a bunch of splinters. Good for making an enemy go blind or getting an infection. If the fragments are larger it's basically a frag grenade. I'm going to keep looking.

I'll update if I find anything of note.


Why not have a gun with a sort of extrusion>melt>cut>shoot through chamber of water to be launched out the other end as a hyper glass cannon

  • $\begingroup$ This doesn't directly answer the question. $\endgroup$ Apr 26, 2020 at 7:43
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    $\begingroup$ But somewhat indirectly gives it a shot. $\endgroup$ Apr 26, 2020 at 14:57

More excitingly, glass under tension can be used as an explosive. The US Army Research Laboratory is researching this; so far the energy storage levels are well below below chemical explosives, but in your world things may be different.


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