Amber is fossilized tree sap and 2 of the main sources are from the Baltic states and the Dominican Republic. Baltic Amber is estimated to be roughly 35 - 40 million years old! These are Genuine Baltic Amber of the Finest quality. All necklaces are handcrafted in Lithuania and sourced from reputable sources
Here is a good link about Baltic Amber if you'd like to find out more:

Item
#M41 - Dark Baltic Amber Faceted Oval Necklace
Clean Dark colored Baltic Amber faceted ovals measuring 7.75x11 to 9.5x12.7 mm. This is a ready to wear necklace with a screw-in clasp is also made of Amber and beads are knotted inbetween. Actual 20" strand shown.
$260 for this strand SOLD