blue/blue gemstones
There are many gemstones that have blue or blue hues. Typical examples include sapphire, aquamarine, tanzanite, Paraiba tourmaline, blue topaz, iolite, lapis lazuli, and turquoise, but there are others as well. Even though it's a blue color, there are some that are more greenish and others that are more purple, and the impression changes depending on the shade and transparency, and the more you know about it, the more you want to collect it.
Karatz GemMagazine
" 10 Blue Gems "