A lot of comments here are suspicious of you, so I'm going to try my hand at guessing whether this was AI.

Since GPTs are hilariously bad at detecting themselves, I'll venture on the human spirit!

First, we establish truth 1: this is copy-pasted.

Although Moissanite isn't mentioned twice, everything after "Synthetic Alexandrite" inclusively is mentioned twice. That means this was procedurally copy-pasted. Someone writing on their own would either CTRL+A then CTRL+C and make no mistakes, or not repeat themself at all.

Of course, we can also look at the half-formalized format that indicates something was copied from raw text and pasted into markdown, rather than formatted with markdown first.

Colon:
words words Colon:
words words Colon:

copy-paster spotted

Second, we cast doubt that a human wrote the source.

• AI-isms vs. non AI-isms

  • Non-reused acronym definitions.

    Garnets like... yttrium iron garnet (YIG)

    This is probably taken straight from the Wikipedia's site description for YIG. Usually humans don't define an acronym only to never use it, unless they're making a mistake, especially not for just making repeated structure. So either Wikipedia was in the training corpus or this was Googled.

  • 5/23 sentences start with "While" (weak ai indicator)

  • no three-em dashes or obvious tricolons are overused (non ai-indicator)

  • no filler bullshit introduction or conclusion (non ai-indicator)

  • obvious repeated structure that you can feel (strong ai indicator)

  • Suspiciously uncreative descriptions (ai indicator)

    "These stones are not just rare but impossible to find naturally, offering a unique and unconventional aesthetic perfect for someone looking to stand out." (emphasis added)

  • Repetition of "unusual" and "rare" rather than more flavorful or useful adjectives (AI indicator)

    • We're talking synthetic stuff. Would a human write about rarity?

  • Superficial, neutral-positive voice despite length and possible source. If this was pasted from a technical blog, I'd expect it to have more "I" and personal experiences, or more deep anecdotal flavor (AI indicator)

    • e.g. use of "fascinating" but doesn't go deeper into any positivities

Third... let's take a guess

So it was copy-pasted from somewhere, but I can't imagine it being from a blog or website, and it isn't directly from Wikipedia. It has some nonhuman mistakes, but is otherwise grammatical, neutral-positive, and repetitively structured. And it lacks that deeper flavor. So.... it was an AI, but likely not openAI.

At least there aren't any very "committal" facts, so the length but lack of depth suggests that everything's maaaaaaybe true...

I wasted my time typing this