During a brainstorm session the idea of the ruler of a maritime empire sitting upon a throne made from worked salt came to me. Before I break out the handwavium there is something that I would like know:
Is salt a workable material?
If melted down could salt be worked into various useful or at least aesthetically pleasing shapes?
If so what would it look like?
You can make stuff from salt. The fine people who worked the Wieliczka Salt Mine did their darnedest to make statutes! From those works, you can see that salt looks a lot like other rocks you find around. You may not even notice until you (or something else) licks it!
Salt itself isn't that hard. The US Department of the Interior has a free .pdf you can check out some of the properties of salt. They talk about different strengths of salt. If you compact your salt, it will be stronger. If you melt you salt together, then it will be stronger still. At its most strength, though, it still very weak compared to steel.
What about molten salt? That's a thing. Depending on what type of salt (like not table salt), you can melt it more easily than metals. Table salt, however, has a melting temperature of 801 degrees C. Like many other properties, that's less than steel. Pure table salt, though, can have a clear crystalline look, which may be very desirable for certain artistic effects.
Can molten salt be blown, like glass? According to this source, the viscosity of molten table salt ranges from $0.0792 mN*s*m^{-2}$ (at 1210 K) to $1.030 mN*s*m^{-2}$ (at 1080 K) (Page 824, table 24.2). $SiO_2$, a common type of glass, has values of viscosity as low as 7.85 $mN*s*m^{-2}$ (at 1500 K) according to this source (page 61). Given this, can you blow it like glass? It appears that molten salt has 1/7th the viscosity of glass while molten. I do not have much experience blowing glass, but I doubt that you could use the same method for molten salt.
You could used dissolved or molten salt in casts, which would allow the salt to form various shapes. Tricky individuals have developed various methods of casting, such as die casting or centrifugal casting, which can make objects of various shapes. Add the solubility of salt in water, and you can smooth any edges or errors from your castings.
It should be noted that there are many different types of salt out there. I've assumed you want to know about table salt. Different salts will look differently. A pure table-salt crystal is clear. With other things in it, it can look white or any other color from additives. If you've had molten table-salt, and let it cool, I would assume that it would be white or clear in color, depending on what other chemicals it took up.
In short, yes, you can use salts for art. You can easily chisel it, melt it, dissolve it, and therefore form it into various shapes. Molds and casts would make various salt shapes possible. You could use a metal chisel and easily chisel whatever shape you would like.
Salt could potentially be poured into a mold and made into some shape, or things could be carved from large blocks of it, but there are far better things to work with.
Salt is an ionic compound, and as such, it's quite weak. Nothing you make out of it will be structurally all that useful. It also forms cubic crystals, which means it will want to break at right angles if you're trying to work with it.
It can be cast into various shapes, but isn't a terribly attractive material. It's whitish and opaque. It also needs to be heated to 1474 degrees Fahrenheit, which, while attainable, isn't trivial for non-functional art.
You need only google "salt sculpture" to verify that a salt throne could work. There New-Age crystal craze has also incorporated salt crystals for artistic purposes.
If you look at the chemistry, there's a few more things a salt-smith may be interested in. seawater salt is mainly Sodium (Na+) and Chlorine (Cl-), with Magnesium at a tenth the concentration of Sodium. If you melt Sodium Chloride, (801 C) you can run an electric current through it [2] to release the chlorine gas, leaving Sodium behind. (Or you can collect the chlorine gas to make bleach or kill people) Sodium is a soft metal you can cut with a knife and conducts electricity well. It could conceivably have some uses. If you separate out the magnesium, it's reactive enough for you to run a magnesium-based engine [1].
[1] http://en.wikipedia.org/wiki/Magnesium_injection_cycle
[2] https://chemistry.stackexchange.com/questions/884/how-did-michael-faraday-melt-sodium-chloride
