Hadean Lands: Marble And Obsidian Doors - Walkthrough by metzomagic.com

Q. How do I open the marble door in the North Arcade, and the obsidian door in Burning Hall East?
A. This is another case where you have to figure out how to modify a ritual - that produces something like what you need - to get *exactly* what you need:

> recall granite solvent (found in Storage Nook, under lead hatch)
"TUCKER'S SOLVENT, which will DISSOLVE ONLY GRANITE: Begin with the Hermetic sealing,
and a mixture of muriatic and bamuriatic acids. Add some elemental earth; use a word of
anaphylaxis. Add a bit of slate - this being the symbolic opposite of granite - and conclude with
the Binding of Antipathy."

> recall facts
> recall periodic table of stone (found in Confusing Cracks, look through oculus)
"We are familiar with earth as a pure element in the Greek system. However, minerals need not
be considered as imperfect approximations of a Platonic ideal; each has an alchemical structure,
and we may discern relations between them. Thus, marble and obsidian are opposites - white
versus black, crystalline versus glassy, pelagic versus volcanic. Soapstone and basalt are another
light-dark pair. Other opposing pairs rely on different relations. Chalk and flint are found
together, but with different qualities. Granite and slate are formed by opposing geologic
processes; so too sandstone and malachite. Porphyry and quartz are an interesting case..."

So to make marble solvent, we use obsidian in the ritual (and vice-versa!) but first we need to make some bamuriatic acid:

> recall bamuriatic acid (found in Deep Stacks)
"THE SYNTHESIS of BAMURIATIC ACID: This substance is similar to muriatic acid, but even
more corrosive and toxic. Exercise caution! Prepare your retort with the mineral fluorspar in a
bath of vitriol. Invoke the sealing; heat until the crystal has entirely dissolved. Discontinue the
heat. Add saline solution, but be sure to first use a word of entension (to prevent a premature
reaction.) Once combined, a word of culmination will allow the reaction to complete in a
controlled manner."

I'll leave it up to you to find out what's beyond the marble door. And then... it seems at first that all we need do to open the obsidian door in Burning Hall East is to make some obsidian solvent, drink fire-resistance to allow us survive the inferno in Burning Hall East, and that's it, right? Go ahead, try it. The trouble with that simple plan is that the inferno consumes everything but you, including that vial of obsidian solvent you're carrying around :-\ So we need to use the fire-devourer to put out the inferno first. You found that ritual under the lead hatch in the Storage Nook too:

> recall fire-devourer
"THE FIRE-DEVOURER (a potion to extinguish even the greatest conflagration): Prepare a
strong fiery environment - several influences should be combined for this ritual. Place a measure
of alcohol into the bound. Begin with a sealing word of passivity to oppose the alcohol's fiery
nature. Ignite the beaker with elemental fire; this will provoke combustion despite the
passivation. Conclude with the Greater Phlogistical Saturation. The resulting potion is of great
strength; one vial, flung into a burning building, often suffices to end the danger."

If you've just done the Dressing Room run, you'll need to reset again before making the obsidian solvent as it requires the fluorspar too. Anyway, I found out by experimentation that making the fire-devourer required 2 pieces of burning wood on the gestalt shelf to satisfy the "...strong fiery environment..." bit. I used: winter-oak and blackwood. And the "...sealing word of passivity..." refers to the phlegmatic sealing formula, which you found in Chasm, at Bridge, by looking through the oculus. So to make the fire-devourer, in the Nave: Click here to show/hide ritual steps

It can be a little tricky figuring out how to put out the conflagration in Burning Hall East. But as it's really just a matter of figuring out how to satisfy the parser, I'll save you the trouble:

Antechamber
The high officers presumably wait here and prepare themselves for the solemn rituals of the
Chancel. That august space is to the north, through a sturdy circular gate, which is closed.

The antechamber itself has nothing in particular to offer. The obsidian door to the west is open.
A narrow hallway runs south, but a fracture blocks it.

Two papers, a neat sheet and a faded sheet, are lying here.

> take neat sheet
"If one of a marcher's dragons becomes disorganized, the vessel is in serious danger. As an
emergency measure, the faulty dragon may be subsumed into an active one, transferring its
functions. The composite will be unstable, but may suffice to rig the marcher to a safe berth.

"Place a fulcrum in the active dragon's lair." (A footnote here: "Any lair will suffice, in fact; the
fulcrum merely provides leverage.") "Prepare an orderly environment and use the Marcher's
Invocation. Follow with a symmetric sequence to indicate a forward transition (active dragon
consuming damaged one). Conclude with the Dracon Invocation. This will summon the active
dragon; one can then translate it to the presence of the other. Warning: do not allow the
dragon's presence to cross the fulcrum node!"

It's going to be a little while before you can make any sense of that, but you will eventually. Trust me :-) For future reference, that's the 'emergency dragon subsumption' fact.

> take faded sheet
"THE DRAGON FULCRUM: This ritual requires a bound of metallic quicksilver, or a quicksilver
amalgam. Place a stone token within, and speak Grendel's Sealing. Pour vitriol onto the stone
(for sulphur and quicksilver are the polar principles of alchemy). Invoke the dragon's name, and
conclude with the Relative Anima." But the words "dragon's name" have been scratched out.
Below them is a smudged knot or tangle of lines - as if someone had tried to copy a
multidimensional structure onto the paper, without much success.

OK... I think these two things together are what we need to get the dragons operational again, don't you? But we haven't encountered any quicksilver (i.e. mercury) in our travels, nor Grendel's Sealing. And that 'multidimensional structure' thingy doesn't exactly look straightforward either. But there's more we can do here, because it looks like we're finally within spitting distance of the ever-elusive Chancel:

> n
(first opening the circular gate)
You reach for the bars, but your fingers go numb and slide away.

This gate has a psychic security stricture as well. It feels even tighter than the one on the
Birdhouse.

Yeah, well that would have been too easy, wouldn't it have? Hmm:

> x gate
This gate is formidible [sic], and forbiddingly shut. Straight metal bars are set into a circular frame. A
psychic numbness radiates from the gate; you can sense it even without coming near.

On the other side of the gate is the Chancel - a modest-sized chamber with an ornate ritual
bound. Its north wall, opposite you, is the ornamented writ screen.

I suppose we need to figure out how to get in there next...