Usually more fantastical ones, but yes, the calcite cave here is the closest we get to it IRL.
Basically, imagine a fairly large-sized cavern with crystals akin to those inside a geode, in many beautiful formations, some neatly aligned, some in a crystal "burst" arrangement, some descending from the ceiling, all gleaming and glittering, some lit from within by preternatural glow. A place where a beam of light seems like it could bounce forever, reflecting and refracting into myriad colors. Fragile and sharp, beautiful and magical.
For me personally, it looks like the darker varieties of blue jade (since it is never all that dark), "imperial" green, violet, and rich red, probably in that order. Darker blue jades are very close to my favorite color (azure, halfway between cyan and blue on the color wheel; aka the color of the center of the sky on a cloudless summer day). Green is of course traditional, and the imperial in particular is quite striking, especially if it's in the middle range of translucency. The violet ones are an unusual color, not common in gemstones, so I appreciate that. And then the red is likewise striking, especially if used for carvings rather than regular stones.
I think it's because most people don't know that Jade come in that many colors. When they hear about the word or read about it, they automatically assume the source is referring to Green Jade. It's the same story for other precious stones like rubies or sapphires.
I was a fan of how 4e portrayed a lot of the gods. There was a great article on Gruumsh and Corellon in either Dragon or Dungeon that took their story in new directions to made their conflict much more interesting IMO. Now I just wish I could remember which issue of which magazine it was!