we have a Goblin Artificer turned to stone and none of the group has level 5 spells. Anyone know what we can do to reverse this?

Nothing definite in the rules. If you want to figure something out, your DM could have you roll some Nature or whatever checks to see if someone might know how to make a cure, possibly using elements from the creature that caused the petrification. Or, a check could tell you whether the petrification caused by said creature is only temporary. Again, something you'd do in-game.

Depends entirely on the nature of how and why they were turned to stone, and whether or not they're still "alive" or if they've died as a result. An interesting plot hook typically used in an instance like this is to harvest the stomach acid (or perhaps blood, I can't fully recall) of a Basilisk in order to create an anti-potion of Flesh to Stone. It essentially creates and oil which, over time, naturally allows the creature affected by petrification to revert back to normal. Greater Restoration is all I could manage to find in my short investigation which specifically states is removes this condition.

There was a Sage Advice notary once which stated Dispel Magic could reverse the condition, but I've yet to locate that column as to the specifics. If anyone else finds it, I'm sure they'll gladly post it here.

There's also the Wish spell, but it goes without saying that's not available to you as of yet.

Honestly, getting 5th level spells is likely your best bet, or perhaps finding aid from a church wherein a cleric, or another class with Greater Restoration available, can perform a service for a fee.

EDIT: Also just read somewhere that another interesting method is to harvest Cockatrice Feathers which are used to craft a sort of balm to reverse the effect.

Most of the methods will be in-game options at the discretion of your DM, but look into creatures which can cause a petrified condition and see if there's any other neat little hooks you can use to go on another interesting side quest!

Option 1 is to level up without him until you can cure him yourself.

Option 2 is to pay a high level caster to cure him.

Option 3 is that if your DM put a petrifying danger into the mix, maybe they also put a reversal mechanism in the mix - a spell scroll of greater restoration or something.  Look around.

Greater restoration removes the petrified condition.

Are you a player or the dm?

This has happened to me as a player and we fixed it by basically finding Medusa’s lair and stealing a stone to flesh potion.

Might be a good opportunity to roll up a temporary character to play until you can figure out a way to restore your main character. Like a mini-death.

i suppose 'how' is a question.  it could just have a limited duration like flesh to stone

Quote from HeathSmith >>

i suppose 'how' is a question.  it could just have a limited duration like flesh to stone

 
Flesh to Stone isn't limited. The spell duration is only the opportunity to break concentration or dispel it before the effect becomes permanent and un-dispellable. 

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OP: this is a "talk to DM" thing. Nobody here can actually help you. The solution will depend entirely, fully and completely up to your DM. 

Quote from Cyb3rM1nd >>

 
Flesh to Stone isn't limited. The spell duration is only the opportunity to break concentration or dispel it before the effect becomes permanent and un-dispellable. 

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OP: this is a "talk to DM" thing. Nobody here can actually help you. The solution will depend entirely, fully and completely up to your DM. 

 fair - probably shouldn't have linked the spell...point being it might not be a permanent effect or that transition period could be days/weeks vs. 1 min...lot of options

This isn't that complicated everyone. Like I said before, greater restoration.

Greater Restoration

You imbue a creature you touch with positive energy to undo a debilitating effect. You can reduce the target's exhaustion level by one, or end one of the following effects on the target:

• One effect that charmed or petrified the target

And then we come to what the petrified condition is:

Petrified

• A petrified creature is transformed, along with any nonmagical object it is wearing or carrying, into a solid inanimate substance (usually stone). Its weight increases by a factor of ten, and it ceases aging.

Seems pretty cut and dry that Greater Restoration is the way to go.

Quote from Xalthu >>

This isn't that complicated everyone. Like I said before, greater restoration.

 

Greater Restoration

You imbue a creature you touch with positive energy to undo a debilitating effect. You can reduce the target's exhaustion level by one, or end one of the following effects on the target:

• One effect that charmed or petrified the target

And then we come to what the petrified condition is:

Petrified

• A petrified creature is transformed, along with any nonmagical object it is wearing or carrying, into a solid inanimate substance (usually stone). Its weight increases by a factor of ten, and it ceases aging.

 

Seems pretty cut and dry that Greater Restoration is the way to go.

👇👇👇

Quote from GTALBOT2018 >>

we have a Goblin Artificer turned to stone and none of the group has level 5 spells. Anyone know what we can do to reverse this?

 They don't have level 5 spells, hence no Greater Restoration.

Xalthu, yes but Greater Restoration is a 5th level spell. This requires a 9th level spellcaster. The party are not high enough level.

Since nobody in the party are able to cast this, it's "DM time".

EDIT: got beat by Naruhoodie. Darn forum ninjas!

Argh, stupid me not reading to the bottom again.

Now I see the problem. Sorry if I came off as a jerk.

A Goblin sized stone statue shouldn't be to heavy to carry or load into a wagon/cart.  I would take your stone friend to a spellcaster to undo it. Probably should make a new, temporary character for your friend to use until the Goblin is restored to normal. Just don't let any stonecarvers near "The Rock" or he may be done for lol.

Quote from Kotath >>

Option 3, the rest of you get turned to stone too. The campaign continues sometime in the future in campaign time when someone comes along and revives you all.... 

 Option 4, the rest of you get turned to stone too, then the rest of the adventure is your party trying to reach the White Castle.

player, level 10 fighter

Quote from GTALBOT2018 >>

player, level 10 fighter

 In that case, the ways that are available are up to your dm. I would suggest questioning NPCs about high level spellcasters in the area, particularly clerical ones. You could also check magic item shops (if they exist) to see if there are any spell scrolls or magic items that could help. Ultimately, it’s your dm’s world, so the resources in the story are theirs to determine. You can also ask your dm, out of game, if they are planning for a way that you could find to bring back the artificer, or if the artificer’s player should roll up another character.