Young adult book about lost realm and magic crystals

[fin3apple]

I read this book I think around 2014 but definitely within the range of 2010 to 2015. I think this book was part of a series, but I only read the first one if that is the case. It was definitely fantasy, and I would guess that it is young adult. It was about a boy and a girl, either cousins or brother and sister, who were both high school age. The boy was slightly younger than the girl and he was much more serious. The girl was more of a typical teenager, and I think a bit of a rebel. I don't remember how but somehow the boy and the girl get transported to another world - possibly this is caused by the father? This new world exists outside of time, in a way. It's populated by all kinds of ancient civilizations who have been living there for a long time, basically not aging. The civilizations include Neanderthals, Aztecs, possibly Vikings or Amazons, and a few others. They also are all able to communicate with each other, which is due to the magical properties of these crystals that are plentiful in this realm. The color of the crystals corresponds to its abilities. One color of crystal acts as a translator. Another color is a source of energy. Another color causes them to live forever. Another color acts as a protective barrier. One thing I DISTINCTLY remember happening is when the boy and the girl end up there they are taken to the leader, who questions either their cell phones or their flashlights. At this point the boy attempts to explain science to the people, but the translator crystal keeps translating the word "science" as "magic". The boy tries a couple of times and then finally is able to say "science", but that has no meaning to the crystal people.

I don't remember exactly what happens next, but I know that the girl joins a tribe of female warriors - likely either Amazons or Vikings. The boy befriends several teenagers of different civilizations, including a Neanderthal boy. I remember that there is a clear class system in the crystal realm, and that the Neanderthals are basically treated as idiot servants. But **SPOILER** they are actually extremely intelligent and faking their stupidity out of paranoia. **END SPOILER**

I don't remember much of the overarching plot but I think there might have been some evil scheme and unrest brewing between civilizations. Also possibly crystals going missing?

Anyway, that's all of the information I can remember. Does anyone know what book I mean? Thank you so much!


**Edit**
This book has now been found, thanks to the much appreciated efforts of the glorious and lovely kaylee66!!!

The title is Jake Ransom and the Skull King's Shadow.

Comments

[kaylee66]

Two cousins being transported to another world by the boy's scientist father sounds like Crystal Doors
https://www.goodreads.com/book/show/849111.Crystal_Doors ...but the rest of it doesn't seem to fit.

The only thing I could find about a world with people from many civilizations who all understand each other is Jake Ransom and the Skull King's Shadow
https://www.goodreads.com/book/show/5278010-jake-ransom-and-the-skull-king-s-shadow
This review mentions a number of different civilizations, including Neanderthals:
https://www.goodreads.com/review/show/62123080?book_show_action=true
and someone else mentioned this world having "crystal alchemy" but that was the only reference I could find to crystals, so I can't tell if they're talking about the same thing as you.

Could it be either of these?

You found it!

[fin3apple]

I did check the Crystal Doors and that's not it, but yes!!! Jake Ransom!! That's exactly it, oh wow, I cannot thank you enough for your help!

Truly, thank you so so much. I think it was my fixation on the whole crystals aspect that was getting in the way of my search, but yes that's exactly it!!!

You're my hero :)

Re: You found it!

[kaylee66]

You are very welcome. :) I'm happy to know that I found the right one!

I also requested it from the library, it sounds really interesting.