I've looked in my Angel Bible, and here are the various angel stones listed that sound like they might be yours:
- Angel aura - quartz bonded with platinum. Described as opalescent. It is iridescent and has rainbow hues in it (to that you can also add aqua aura - I have a pendant made of aqua aura, and it's very angelic - quartz bonded with gold, which makes it iridescent blue). Linked to your Guardian Angel.
- Celestite: described as sky-blue, white or bi-coloured, and can have tints of red or yellow. The appearance is tablular blades or pyramidal shape. Also called Celestina. The author calls it a "master teacher for the New Age". It helps calm the emotions, and is related to the throat chakra, and is very helpful for people who absorb other people's energies too easily. Linked to the Celestial Guardians.
- Tanzanite: it can be any colour between sky blue and lavender. It is rare and it is trichroic - it reveals different colours when viewed in different directions. It is used for inner and outer journeys, and is purely spiritual in nature. Linked to the archangel Tzaphkiel.
- Iolite: indigo, blue or honey-coloured. Very powerful visionary stone, described as "the New Age vision and prophecy stone". Linked to throat and third eye chakras. Can be dangerous to those whose lower chakras are not fully balanced. Linked to the archangel Zadkiel.
- Blue topaz or aquamarine, but both of these have been very well known for millenia.
The book was published last year, however it's possible that this new stone didn't make this edition, if it's only been mined for the past 2 years.