This is Die Kristallkönigin, an unfinished story by Irene Salzmann and Eric Grivel. There are 16 chapters, accessible directly from the following links:

1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16