My husband’s is December! My son’s is October so actually all four of mine will look nice together since two are the same, the December is a different blue, and October is opal! Well October is sometimes pink (tourmaline) but I’d stick with opal personally!

My birthstone is the blue topaz (December) and I'm picky. I like the London blue, which is the darker one like sapphire but has a tiny bit of green. I'm not a fan of the traditional Swiss blue. My husband is amethyst, so I won't be getting a ring with all 4 months because the purple and yellow and 2 clashing blues won't look very pretty haha

My birthstone, too :)

Gorgeous blue! I am a sapphire birth myself so I have quite a bit of gifts that were sapphire. Truly is a gorgeous birthstone in my mind...maybe I'm biased.