Crystal sword...

[malloyd]

Originally Posted by Bruno

Composite materials may be the only way to go here, a plastic core and a sapphire coating, perhaps?

The fundamental problem is that the property that gives metals toughness (the electrons and to some degree the nuclei are free to move around without disrupting the structure) are the same property that allows them to absorb a broad range of frequencies of light well.

Transparent plastics can be tough too because long carbon chains can flex, allowing the nuclei to move some relative to each other too. But if you bend a piece of transparent plastic sharply and look at the place where it's most bent you'll probably notice it goes opaque there, move them *enough* and you disrupt the local ordering that allows transparency. Still polycarbonate plastic is probably the closest you can come. There are some machine grades designed to tolerate vibration and repeated stresses that might not be *too* terrible. Keeping a razor edge on them probably isn't happening, but you don't need razor sharp for a sword to hurt.

Ice, held together by hydrogen bonds that likewise still work when the distances are wrong, might be another halfway decent material - not so good for humans, but hey maybe you're designing weapons for a species that lives in liquid ammonia... I understand there are some polyvinyl alcohol composites that are interestingly strong and tough because of the hydrogen bonding.

[Refplace]

Originally Posted by malloyd

Ice, held together by hydrogen bonds that likewise still work when the distances are wrong, might be another halfway decent material - not so good for humans, but hey maybe you're designing weapons for a species that lives in liquid ammonia... I understand there are some polyvinyl alcohol composites that are interestingly strong and tough because of the hydrogen bonding.

If your going with magicI would suggest invisibiliyy or glasswall variant on the blade. But a renewing ice sword is cooler.

[AlexanderHowl]

There are various types of amorphous metals that are transparent (usually alloys of palladium and silver). Some of the reasons why silicon glasses are so brittle are because of atmospheric contamination and microscopic defects caused by gravity and vibrations during formation. A properly designed facility in LEO could potentially make silicon glasses with strength and toughness that exceeds steel. Imagine superfine blades made from silicon glass forged in LEO or superfine scalpels made from that same material?

[Anthony]

Note that if it's acceptable for the blade to only be partially transparent, you can use plastic with an edge of a different material, though other than looking cool it's not obvious why you'd want to do this (possibly for an electric weapon, you want two conductors with a nonconductor between them. Normally that's air, but if you want durable enough to parry with plastic might be good).

[Bicorn]

Originally Posted by Refplace

But a renewing ice sword is cooler.

Pun intended?

[Flyndaran]

Seems like it's just not possible without at least some magic.
Whether ever-frozen ice, shatterproof glass, or purely magical "gem"...

[Prince Charon]

Originally Posted by Refplace

If your going with magicI would suggest invisibiliyy or glasswall variant on the blade. But a renewing ice sword is cooler.

I've seen swords made of ice in some stories. I think there was one in GURPS Witchworld, but if so, I'm not sure where in the actual Witchworld series it was introduced. I might be mixing it up with Fantasy (3e) or one of the Magic Items books, though.

[Fred Brackin]

Definitely a job for magic rather than science.

Essential Stone is already equated to "Adamant" and nothing says it can't be transparent. As a bulk defensive material it's close to iron and 3x lighter. 3x harder than granite ought to take a good edge. I generally insert a "melted in Essential Fire" step for magical production. You can always Shatterproof it too.

You can also cheat outright and Enchant Transparency on a steel blade. Making it glow too is about the same level of expense. Mount the blade so it can retreat into a Hideaway in the hilt and you can fool people into thinking that you have an energy blade. Flaming Weapon and a humming noise are extra :)

[mr beer]

Originally Posted by Prince Charon

I've seen swords made of ice in some stories. I think there was one in GURPS Witchworld, but if so, I'm not sure where in the actual Witchworld series it was introduced. I might be mixing it up with Fantasy (3e) or one of the Magic Items books, though.

Dragonlance had ice weapons IIRC, carved from the heart of glaciers or somesuch silliness.

[Paulon]

Frostreavers. They melt when they get above the freezing point.