December Birthstone: Blue Topaz

I am not entirely convinced that December's birthstone is blue topaz.  I'm a December birthday and there was an old poem I've heard that says if you were born in December then you're cold, so you warm your hands up with turquoise stone.  And my family has always collected turquoise for me, so who knows.  Another weird thing- I was always told that my astrological sign was "on the cusp" (Sagittarius and Capricorn), but now they say I am just Sagittarius.  So I've been reading the wrong horoscope for 20 years???  LOL!!

Happy Birthday to my fellow Decembers!

and what do you think.... blue topaz or turquoise??