There are several people who will have no idea what a Paraiba tourmaline is, let alone how precious it is. Tourmaline is a mineral, which is crystalline boron silicate in nature and is classified as a semi-precious stone. The stone comes in a variety of colours, but its actual occurrence is not so common, which is what makes it so special. The Paraiba version of it is all the more precious, because it comes from the Mina da Batalha in the Federal Brazilian State of Paraiba.
This is the kind of information you would get only with a specialist and someone who really understands the geology of all these stones. For instance, you would know that you could find a blue sapphire with any jeweller of repute, but you might have not known that sapphires can be of several other colours. Similarly, only a good gemmologist will be able to tell you in detail about how a particular gem has been sourced and whether it is really genuine or not.
When you are investing in an expensive stone such as the pink sapphire, you need to be sure that you are getting true value for your money. This is why it is imperative that you purchase through a reputed dealer, someone who deals in retail as well as wholesale, is willing to give you the lineage of the stone, as well as the guarantee that the stone is authentic and responsibly sourced. Someone who designs and crafts customised jewellery, along with all of this, would be your best bet!