Pure Pink Topaz is a natural topaz, mined in Brazil, and it has been Titanium treated in much the same manner (and by the same people) as the Mystic Fire Topaz I've sold online for 6-7 years now.  This is a very stable process, and you don't ever have to worry about the color fading.

These are 6mm rounds set in a traditional basket mounting in 14k gold, hanging from gold leverbacks.