Sure, it's not doing anybody any good down here. Same goes for the shiny chest; what's in it?

Shiny chest contains a stick of dynamite, a glowing arrow (or thirty-seven arrows, depending how you look at it), an eyeball that makes her distinctly uncomfortable even beyond the usual discomfort of finding an eyeball in a box, and an unusually shiny pocket mirror.

Margaret puts most of that in her infinite pocketbag, and then starts an internal debate.

She does not want the disembodied eyeball.

But what if it's an important component of something?

Nothing that requires disembodied eyeballs can possibly be that important.

But what if there's a way to get home?

That's ridiculous; there's not going to be a recipe for a way home that calls for a disembodied eyeball.

Alright, maybe not a way home, maybe just a really powerful healing item or something. 

Still not worth having an eyeball in a box in her pocket over. Anyway, she can leave it here and come back for it later if it turns out to be important. 

But, but but.

Her pockets are staying eyeball-free and that's final. Is there anything else in this house or this cavern worth examining?

There's a pot over here containing a stack of fifty copper coins. Other than that, no.

Also, the mirror says it'll take her back to the surface. (Technically it says it'll take her "home", but that concept expands to "the place she last woke up" upon examination.)

Copper coins: much more worthwhile. Mirror-based shortcut: sure, why not. 

There's a whirlwind of blue sparkles, and she's standing in the house she built. "Try turning your ores into bars and making some armor, or a better pickaxe," Eric says by way of greeting.

"Hey there, Eric! A better pickaxe sounds great. Armor would need to be really pretty to be worth it." She sits down at her furnace and starts in on making bars. What kinds of pickaxes, regular axes, and potentially other tools can she get now?

She can make an anvil out of the surprisingly sturdy lead! An anvil appears to be required for any heavy-duty metalworking, sensibly enough.

"Armor can be worn under other clothing," Eric says. "It's surprisingly comfortable!"

Margaret grins. "Eric, that remark made a surprising amount of sense! You'll pass the Turing Test one of these days, if only because I'll have gone too crazy to be good at administering it. I'll see what my magic thinks of local armor." She starts getting some use out of her new lead anvil.

"They say there is a person who will tell you how to survive in this land... oh wait. That's me."

Her best material at the moment is platinum, but she doesn't have enough of it to make anything useful, unless she really wants a nice axe or sword. (Eric reminds her that that "a Diamond Staff can be made with ten bars of platinum and eight diamonds.") Tungsten is her next best bet, and she's got plenty of that; enough for a full suit of armor and either a pickaxe or helmet. She's also got plenty of lead, for her axe and hammer needs. 

She'll leave the platinum alone for now and see what tungsten armor looks like.

It's... green. And periwinkle. It's got a somewhat coherent aesthetic, but that's kind of all you can say for it.

"You can designate a piece of equipment as a vanity item and it will lend its appearance to something occupying an equivalent location," Eric says.

It's not painful to look at or anything, but her standard is "looks like a brilliant seamstress got handed the budget of a royal treasury", so, ew. If she puts it on under her other clothes does it show through the lace or mess up how things hang, or does it play space-warpingly nice the same way the mining helmet accommodated her horns?

It fits like a second skin. There's a sense of protection, inherent like the feeling of safety from the heart candies, but it feels somehow incomplete. Maybe it wants that transcendently ugly helmet? She could always make a lead pickaxe for now...

That is shockingly cozy, and if she keeps the helmet off she shouldn't suffer any ill effects other than possibly fewer prophecies. Maybe she can wear it when she's mining or star-catching or otherwise looking for fights and leave it off the rest of the time--how fast can she get it on and off?

More or less instantly!

There seems to be another option, now that she's actually wearing it, to designate a "vanity item" like Eric said. Her dress for the armor, her pants for the greaves.

Oh, she can use her magical girl clothes as a vanity item? If that fixes the color clash, she can just go around armored all the time. Convenient! She'll take the lead pickaxe, too, if it's better than the previous one.

The armor vanishes when she designates vanity items, though she can still feel it protecting her.

With the helmet she can feel the full effect snap into place. The armor is more protective with full coverage, even though it doesn't visibly exist, and she feels like she could mine faster. The lead pickaxe helps with that too.

Awesome! Invisible armor is the best kind of armor. Time to see how fast she can mine now!

Pretty fast! Mining before was pretty effortful, but now it's... still effortful, there are definitely still upgrades she could make, but it's a lot easier, especially when she's just cutting through dirt and stone.

"Wow, this is easier. Still hard, but hey, gotta stay fit. Assuming staying fit is even a thing with the weird physics here." She's sort of talking to Eric, except for how Eric isn't in this mine.

Eric, not being in the mine, does not respond. She finds a small cavern full of diamonds.

...There's a feeling like something is watching her. Also, her dangersense is going crazy.

Magic staff in one hand, sword in the other, blink into starscape and thicken up her scales under the armor since there's no room to fly in here, start backing up the tunnel unless the danger is coming from behind her.

The danger seems to be coming from above, even though the tunnel ceiling is just above her head.

Then the danger is either some animal that can burrow through rock, or an imminent earthquake (planetquake?), and either way a tunnel is the worst place to be. She mirror-teleports back to her house, then heads outside in case it's the second thing.