If a man had the right paraphenalia, this could be a profitable fact. Because in their pure form the Powers have... well... power. A phial of pure Fire, a drop of pure Ocean, a puff of pure Sky; all are deeply powerful magical artefacts with many, many uses.
It's possible that in the Dreamtime and maybe even at the start of the First Age these pure essences of Power still laid about the landscape ripe for the using, but it's very evident that this is no longer the case. A handful of earth from the ground does not pulse with magical energy. If you light a candle, the flame does nothing except burn your finger if you put it too close. And alchemists know the reason why.
They're no longer pure.
All the pure samples of essence have been used up. All that's left are diluted and impure mixtures. But with the right equipment, the right recipes and a healthy disregard for your own personal safety, they can be purified, distilled and made into the essence of a Power, a substance that's veritably pulsing with arcane power.
All well and good. But every time you create pure Essence, you're effectively chopping off a bit of a Power and running off with it. The Powers don't like this. As far as they can be said to have an agenda, "wiping the smug smiles off the faces of troublesome alchemists" comes pretty high on it. Followed by "recovering the bits of me that I've lost and reabsorbing them, via my shamen or daimons if necessary". The Powers don't approve of their shamen doing any distilling themselves. (As an analogy, if someone cut off your arm and started using it to reach high shelves, you'd be quite pleased if a friend handed it back to you and sewed it on. But if said friend offered to cut off your arm for a bit on the understanding that he'd sew it back on when he was done, you'd tell him where to go.)
There's also the fact that while alchemy isn't actively illegal in Horizon, you do require a licence to produce or possess Essence. (Though you don't, for some reason, need a licence to possess a magical item produced using Essence.) To get one, you need to apply at the Ministry of Public Works. An Alchemist's Licence requires a lot of things of you.
The Alchemist's Licence gives you the right to carry Essences with you and the right to manufacture Essence. It does not give you the right to sell Essence; the licence for that is far, far more expensive.
As a result, the only people who own such licences are people whose professional work involves alchemy: instructors at the Imperial University, government-sponsored advisors, and the like. Alchemy is, in general, performed in back alleys, basements and other places where the Watchdogs aren't going to notice.
Obviously, for more complicated applications of essences you're going to need a purer sample. For these purposes, there are three grades of Essence: Coarse, Fine and Pure. Coarse is perhaps an inaccurate term for the stuff. It still requires a great deal of time and effort to make, and it's still extremely, extremely pure. A single sample of Coarse essence can go for a guilder or two (a Notable purchase).
Fine essence, on the other hand, is far more potent. It is still not entirely pure, but we really are talking only about trace elements here. A sample can fetch as much as a hundred Guilders (a Major purchase).
Truly pure essence is the stuff of legends. The appearance of a truly pure sample is major news around the world; the means to produce it was lost with the Emperor (though countless charlatans *claim* to be able to make it). Certainly there is nowhere that a pure sample is publically known to exist. If some did indeed come onto the market it'd go to the highest bidder, which may well turn out to be a country (a Staggering purchase).
Essence is most definitely not sold over-the-counter: if you spend a turnsheet action, you will be able to find somebody willing to sell you a Coarse-grade essence. Finding someone willing to sell you a Fine essence requires much more time and effort. Making Essence for yourself is considerably cheaper. The reagents for Coarse essence cost only a few shillings (a Minor purchase) and for Fine essence it's not too bad either, being only about thirty Guilders (Significant purchase). However, it costs time, and you need the appropriate Alchemy skill.
To make a sample of Essence requires several consecutive turnsheet actions. (How many exactly will depend on what grade of Essence you're trying for and how skilled you are as an alchemist.) Your first action states what kind of Essence you're going for and whether you want it Coarse or Fine. The others are just along the lines of "continue distilling my Coarse essence of fire". Because this requires a lot of attention (we're not baking brownies here) you can only spend one turnsheet action per turn distilling an Essence in this way. When you're finished, you get your essence.
The process can be sped up. It's widely acknowledged that if you can get really good-quality ingredients, the process of producing the substance is substantially shortened. It's assumed that all alchemists don't automatically know where to get such quality goods; you'll have to find out during the process of the game.
The process can also be slowed down. If you're sufficiently destitute not to have a room where you can stick your equipment so that nobody nudges your crucibles, then the process will take one turn more than normnal, and none of the above bonuses apply. (A Lab automatically counts here.)
Essence can be diluted and concentated. If you already have two units of Coarse essence (of the same Power, naturally), and you're a Journeyman or Master alchemist, you can mix them together and concentrate the solution into a Fine essence, the process only taking one turnsheet action. Likewise, if you have a unit of Fine essence, you can dilute it down into two units of Coarse essence; but this is rather more time-consuming, taking three turnsheet actions (you need to make sure it doesn't get *too* far diluted, or you've wasted your essence). Having a specialisation in the kind of essence you're using will take a turn off the time, as per normal.
Just being an alchemist doesn't automatically mean that you can sell the stuff. Like we say, nobody sells Essence over the counter. You need to find a buyer yourself. If you meet somebody in session who's willing to pay for the stuff, then selling it to them is only a housekeeping action and doesn't need to be detailed. Otherwise, it takes a Turnsheet action spent hanging around a drizzly alley at night to find someone who wants to buy your stuff. The GMs do not guarantee that the man you sell your goods to will then vanish into the sea of Unnamed NPCs and be forgotten about, either. Selling dodgy (and possibly explosive) wares is like that.
Normally recipes will call for a certain grade of a certain Power's essence. If you're desperate, you can substitute a higher grade essence for a lower grade essence, but this won't make the recipe more effective in any way; it just means that you waste the extra effort you put into getting a particularly pure sample.
Regardless of recipe, though, there are a couple of things anyone can try with an essence-- and the effects of these *do* change with the grade of essence.
1. Drink it
Drinking an essence will increase your affinity with the relevant power. You will become more attuned to that power's particular worldview. This is probably not a good thing if you made the essence yourself, because the Power is already mightily pissed off at you, and merely drinking a bit of it doesn't mollify it one bit.
Drinking an essence also has a temporary side-effect, depending on which Power it is:
This is nice and simple. A Rough sample has no effect. A Fine sample has the effect of a Rough sample. A Pure sample has the effect of a Pure sample. Sky, naturally, can't be thrown at someone: refer to the rules for pouring it on the ground if someone makes a Sky-essence grenade.
3. Pour it (or throw it) on the ground
Some sample recipes are below, but it is of course possible to research your own.
Phoenix egg (requires Coarse Fire: Fiddly)
What do you get if you take an ordinary hen's egg, lay it on a table and pour over it a sample of essence of Fire? An unstable bomb ready to go off, that's what. The Phoenix egg is warm to the touch, rocks gently, and explodes into a cloud of flame when the shell is broken. There are stories of them inadvertently "hatching" in peoples' pockets if not used quickly enough; people have also tried using other birds' eggs, with varying results.
Burning Banner (requires Fine Fire: Involved)
First, you need a banner carrying an incendiary symbol. Something that'll make people angry. The Imperial coat of arms would do nicely for this one. Burn it, using your Essence of Fire, and collect the ashes. Paint something incendiary with them: a slogan, a symbol; or if you've got a small enough brush, a short essay on why Colonel Zero is the pawn of Versinya. Anything that'll get people angry.
People who see it will be moved to anger and then to violence. If they agree with the point you're making, they'll fight for it; if they disagree, they'll fight against it.
Elixir of Passion (requires Coarse Land, Coarse Fire: Fiddly)
What do you get when you mix the Land's fertility with the Fire's emotional outburst? Well, the most likely thing is a few nights in the Doghouse for disturbing the peace, an appearance in the gossip columns of the less reputable newspapers and some very odd looks from the jailers. This dangerous little number can be slipped into drinks and is pretty much guaranteed to cause certain... appetites.
Elixir of Love (requires Fine Star, Coarse Land: Involved)
This is the other side of the coin on which the Passion Philtre is one half. With the Stars replacing the Fire, this potion no longer stirs up passion; it inspires emotion. In particular, it inspires love. When making it, the final ingredient is a single tear; the person drinking the potion falls immediately in love with whoever the tear belonged to. (If they're not in the immediate vicinity, the drinker simply realises that there's an enormous hole in their heart that needs to be filled, but doesn't figure who they have feelings for until they actually meet the tear's owner.)
Elixir of Truth (requires Coarse Ocean: Fiddly)
Once you've got a sample of Ocean essence, if you mix it with the right salts it turns itself into a truth potion, without any of the added inconveniences of the subject finding out the secrets of everyone around him. People under the influence cannot speak anything except the truth, the whole truth and nothing but the truth. They can't exaggerate, they can't lie by omission, and they can't bend the truth. It lasts for about ten minutes.
Tidal Ram (requires Fine Ocean: Fiddly)
You need some sort of long, heavy object for this. Something you could use as a battering ram. Hollow it out and cover the inside with a layer of wax. Wait for this to cool. (This is to waterproof the inside, so that when you pour essence of Ocean in it doesn't seep out.) Pour the essence in, and close the lid. You now have a battering ram. A battering ram that'll swing itself. You just need two people to get it started and hold it upright, and soon you'll have the power of the waves smashing down doors.
Scrying Pool (requires Fine Ocean: Painstaking)
A flat silver plate is expensive (a Notable purchase) but once you've got one, you can pour diluted essence of Ocean into it and have yourself a nice flat scrying pool-- although maybe the phrase "scrying puddle" would be more appropriate. With it, you can focus your attention on any one thing you name. It doesn't give you sound, and you can't have it look for things ("Show me Benny Boggis" works, "Show me Leene Square" works, "Find the bastard who took my wallet" doesn't.)
Resilience Treatment (requires Coarse Land: Involved)
The resilience treatment involves mixing your Essence of Land into an ointment and then rubbing it into the skin of the lucky recipient. The result is vastly improved strength and resistance to all sorts of poisons and disease, which lasts until the subject has a wash (thus cleansing themselves of the ointment). The rumour that the Irgarim use this one just keeps on bobbing up. Partially because of their legendary drinking skills; partially because it'd explain why they never wash.
Golem (requires Fine Land: Painstaking)
Ever wanted your own statue to order around? Now you can have one. Carve some instructions onto the forehead of a stone or clay statue, and rub the Essence onto it over a period of several weeks. It'll move and carry out those instructions as best it can. The larger the lettering and the simpler the instructions, the better. Should the instructions ever be removed (if the head's smashed, or if they're just rubbed off) the golem turns back into a statue, and if they get changed or added to then the golem starts following its new instructions as well. In most parts of the world, golems tend to get smashed by angry mobs pretty much as soon as they're noticed. If the statue is particularly large, you are likely to need more samples of Essence, or perhaps even a Pure sample.
Slipperiness (requires Coarse Sky: Involved)
A bit like the Resilience Treatment, this one, but instead of making you strong it makes you hard to restrain. You can bend your joints out of place, slip out of ropes, and generally resist efforts to hold you down. Again, it lasts until you wash.
Flying Carpet (requires Fine Sky: Painstaking)
First, get some salt and drop it into your sample of Sky Essence. Wait until the salt has absorbed all the Essence, then grind it up and fill a cloth bag with it. Now you need to weave a rug, using only material that has been threaded onto a needle and run through the bag. It's a bit of a daunting task, but it's worth it for the ability to zoom about the sky on a flying carpet. Even if it does put you worryingly close to any Sky-daimons who would rather like to liberate the essence bound up in your carpet.