# Rare amethyst type **URL:** \ **Category:** Factual Questions\ **Created:** [February 9, 2025, 5:35am UTC](https://boards.straightdope.com/t/rare-amethyst-type/1014081 "2025-02-09T05:35:03Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![jackdavinci](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jackdavinci/32/3259_2.png) [@jackdavinci](https://boards.straightdope.com/u/jackdavinci)\ **Post date:** [February 9, 2025, 5:35am UTC](https://boards.straightdope.com/t/rare-amethyst-type/1014081/1 "2025-02-09T05:35:04Z")
I was watching a video about gemstones and one of the ones listed was a giant amethyst cathedral geode. They said it was a rare type, and I thought they called it “frogs eye” but I can’t find anything if I search for that term. I assume I misheard, does anyone know the correct term? It’s the ninth item (youtube dot com) /shorts/Oe8RxrunMRA ---
**Author:** ![Darren\_Garrison](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/darren_garrison/32/92_2.png) [@Darren\_Garrison](https://boards.straightdope.com/u/Darren_Garrison)\ **Post date:** [February 9, 2025, 6:55am UTC](https://boards.straightdope.com/t/rare-amethyst-type/1014081/2 "2025-02-09T06:55:04Z")
I would take the commentary with a grain of salt. I noticed at least one error, where they said that grape agate is an agate that looks like grapes, but grape agate is not agate. > **[Grape Agate](https://en.wikipedia.org/wiki/Grape_Agate)** > > Grape Agate is a market name for purple aggregates of tiny quartz crystals with botryoidal (spherical) habit. Mineralogically speaking, grape agate is not an agate and is actually botryoidal purple chalcedony. > It occurs in Indonesia and has also been found west of the Green river in Utah.: 75  > > This article about a specific mineral or mineraloid is a stub. You can help Wikipedia by expanding it. ---
**Author:** ![MrDibble](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mrdibble/32/114_2.png) [@MrDibble](https://boards.straightdope.com/u/MrDibble)\ **Post date:** [February 9, 2025, 9:14am UTC](https://boards.straightdope.com/t/rare-amethyst-type/1014081/3 "2025-02-09T09:14:46Z")
I mean, agate is either patterned or transparent chalcedony, so it’s not far off. And for common commercial mineral names, there is no standard, anyway. As to the OP - the only mineral I know that has a variety called frog’s eye is spessartine, and that’s based on crystal habit. I guess it’s possible for other species, just not anything I’ve ever encountered. ---
**Author:** ![pjd](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pjd/32/3009_2.png) [@pjd](https://boards.straightdope.com/u/pjd)\ **Post date:** [February 9, 2025, 10:29am UTC](https://boards.straightdope.com/t/rare-amethyst-type/1014081/4 "2025-02-09T10:29:28Z")
Maybe @rockdoc1 can throw some light on the subject. ---
**Author:** ![rockdoc1](https://avatars.discourse-cdn.com/v4/letter/r/45deac/32.png) [@rockdoc1](https://boards.straightdope.com/u/rockdoc1)\ **Post date:** [February 9, 2025, 5:28pm UTC](https://boards.straightdope.com/t/rare-amethyst-type/1014081/5 "2025-02-09T17:28:10Z")
I’m no expert, but Ive never heard of frog’s eye before. That amethyst cathedral is in the form of crystals, not agate, and looks to me like the literal millions of others out there on the market and in museums. I could link YT videos with mineralogical misinformation all day if I was motivated enough to. ---
**Author:** ![jackdavinci](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jackdavinci/32/3259_2.png) [@jackdavinci](https://boards.straightdope.com/u/jackdavinci)\ **Post date:** [February 15, 2025, 9:42am UTC](https://boards.straightdope.com/t/rare-amethyst-type/1014081/6 "2025-02-15T09:42:56Z")
Thanks guys! I was also wondering though if maybe I just misheard it, and there’s some mineralogy term that sounds vaguely like frogs eye? Fragzite or something like that? ---
**Author:** ![MrDibble](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mrdibble/32/114_2.png) [@MrDibble](https://boards.straightdope.com/u/MrDibble)\ **Post date:** [February 15, 2025, 4:29pm UTC](https://boards.straightdope.com/t/rare-amethyst-type/1014081/7 "2025-02-15T16:29:59Z")
No, he definitely said “frog’s eye amethyst”. But given he starts the video with a description that is absolutely, utterly, completely full of shit (Almandine is _the_ _ **most** common_ kind of garnet, and found _globally_), he very possibly just plucked it out of his ass. Or he made it up because the rounded crystal habit of the amethyst in that geode is a little more spessartine-like than the points usually associated with geode amethysts. But frog’s-eye spessartine isn’t called that just because of its habit, it’s _also_ the colour: [![](https://cdn.irocks.com/storage/media/12798/conversions/spess-23a-large.jpg) ](https://cdn.irocks.com/storage/media/12798/conversions/spess-23a-large.jpg)