They are members of the CPAA, so probably safe to buy from.
Their website is weird because they have a whole page of out of stock links on the link you gave.
Also, bottom line in my opinion, this is mass produced Chinese pearl jewelry and I don't love that stuff being featured here. If it is not, my apologies to the manufacturers, but they couldn't have achieved a look more like mass produced Chinese jewelry if they tried. I actually like the turquiose and pearl multistrand necklace.
There is a huge market for it, but we don't feature mass production sites of jewelry made out of beading pearls here, unless they are handmade and one of a kind.
http://hgpearls.com/Artisan-Collection-Maria-Double-Strand-Turquoise/M/B0035CZ56O.htm is the necklace I like. However, it costs less than $10 in materials, probably not even $1 for the pearls and about $3 for the turquoise at their manufacturing site. I gag at the $189 price. These guys are wannabee Imperial Delta pearls, except probably not on HSN and we don't feature their pearls here, though we have great respect for the owners of the company.
I prefer the links to the handmade jewelry of some of our members on Etsy and Artfire.
So buy whatever you want, they are perfectly safe or you can complain to the CPAA.