1. "Building on Gemini 4 Argon". 2. Same price. 3. Relatively short time between releases.

Makes me think it's further post-training of the same model.

IIUC, that was all the Flash releases from 3.5 to 3.8

For Gemini that is a foundation model version 3.1 3.5 4 etc. and there is checkpoint on evolution of those specific models. Gemini 4 had Argon - B<> - Carbon and who knows they might have Dysporsium or Europium.

Or you might get Gemini 5 Arizona.

I’m just even more confused

Yes.. very confusing names. Carbon is the next iteration of Argon.

Carbon is like Opus

Argon is like Sonnet

Helium will be small and squeaky I presume

I'm surprised no one at Google realized that both OpenAI and Anthropic's naming schemes follow a fairly clear progression and that they should do something similar to reduce confusion. I would have assumed the opposite given that Argon has a higher periodic number

Lots of commenters here are confused by Luna, Terra, and Sol still haha.

That's on them imo. The point is consistency

It isn't obvious that a fable is "better" than an opus either.

Originally the model tier that was better than Opus was called Mythos, which makes sense. Fable makes no sense, since a fable is just a small story with animals. They should have used "Legend" rather than Fable.

So Argon was 4.0 Flash effectively? Interesting that there is such a small gap between their new Pro and Flash tiers

I don't think that's right. Carbon and Argon have the same price.

I suspect they're using a new naming convention because they had previous contractual obligations tied to the "pro" and "flash" naming, and by switching to a new naming schema they avoid those commitments.

Both seem to have the same pricing: $2 in / $10 out initially, rising to $4 in / $20 out after the introductory period. That made me wonder whether Carbon might be Argon with additional RL training. What’s the Opus/Sonnet comparison based on?

Carbon is Fable / Astra level. Argon is their Opus / Sol.

then why are both priced like sonnet?

They didn't pay the Nvidia tax

No, it's not. The naming is just bad. It's the next iteration of Argon