Fantasy book, two kids end up in a fantasy world where they are hunted by the queen living in a mirror/glass castle.

[Christina]

Fantasy book about two (possibly) siblings, a girl and a boy that accidentally go through a wall in their garage and they end up in a fantasy world (i'm going to try my best to remember details, i think they were pulled through the wall on purpose by someone from the other world)

There's a castle i think made of mirror or glass and a queen that is really evil and sends her guards to hunt down the kids. At some point they get split and each has their journey for a bit. I don't think they has special powers but that's a bit of a blur. Also not exactly sure but I think at some point they manage to get out of the forest and they end up inside the castle.

It possibly was part of a series because the end was more of a cliffhanger and seemed to be continuing in another book. I only read the first in 2013.

If it helps, the cover had a grey colour palette with the evil queen that has really long black hair and the pointy and fragile castle in the background that looked like a thin pile of glass.

Many thanks for taking your time to read that! I don't have much hope but maybe one day I'll actually find the book that got me into fantasy! Any suggestions of which book that might be are really appreciated!

[Capn]

Gates of Glass, maybe? It's not new (1987), though. And there's only the one edition on here, with this cover:

A fantasy adventure story—what happens when Julia finds herself on the other side of her bedroom mirror, in a strange, beautiful, but also frightening world of glass.

[Capn]

There's also a list that may have caught it:

Portal is House/Building:
https://www.goodreads.com/list/show/1...

[PaulGamerBoy360]

The 10th Kingdom by Kathryn Wesley

It depicts the adventures of a young woman and her father after they are transported from New York City, through a magical mirror, into a parallel world of fairy tales.

In a hidden realm, fairy tale characters inhabit nine magical kingdoms where an Evil Queen plots to rule them.

First published January 2, 2000