Take a diamond grit bead reamer, and ream some sawdust from one of the holes. Immediately sniff the dust on the reamer. Obviously make sure the reamer is clean and odorless first. If it smells like pine oil, then you likely have real amber. If it smells like plastic, it's probably polystyrene or acrylic. A warning, though - I suspect the Chinese are making some sort of amber substitute that smells like pine by adding actual pine oil to plastic resin. That way there is a pine odor when tested. Trying to identify amber substitutes is NOT easy!
Another test would be to hold a bead under very hot water until it heats up, then try to sniff out an odor. But, you already said you heated one of the beads - how hot did it get, and did it give off any odor?
More destructive - try to push a hot needle (heat to red hot in a flame, holding with pliers) and then carefully sniff for an odor.
Thank you Rosanna, I have already tried to warm the hole, but it won't burn easily, I've also tried burning the whole bead, but doesn't melt. I just wanted to know if anyone knew about new fakes being made in China with this look.
The thing is that it smells like natural resin, but you also said that chinese are adding pine oil to synthetic resin, and that is what I have suspected.
And I've been offered such a big amount that it is not possible that they are all real amber with this big sizes!
I'd be very interested in having one of these beads for analysis. I plan to send a few beads to an analytical lab to identify the plastic resin used - sometime in the near future. Would you be willing to sell me one bead? Please use the private message feature to reply.
Have you tried a bead in a dish of salty water to see if it floats? Real amber floats. Not sure what the ratio of salt to water should be but as an example, genuine Baltic amber can travel to other countries floating on the sea.
Here's an interesting link.
http://www.wikihow.com/Test-Amber-Gemstones
I recommend three tablespoons of salt to 8 ounces of water. Much more information here:
https://groups.yahoo.com/neo/groups/amberisforever/info
The density or specific gravity of amber is about 1.05 - 1.10 g/cc. Polystyrene (without any dense additives) runs 0.96 - 1.05 so it may not be possible to distinguish amber from polystyrene by floating in salt water. Some additional tests may be needed if the beads float and don't look like, or smell like, amber.
This ad from alibaba shows some beads similar to yours, but not quite the same dark brown color. Place of origin is listed as Nepal, with a price of $98.82 / kg. Material is "synthetic (lab created)", but it is also noted that "Each stone is unique in it's shape. Comes in different sizes." So I suspect the beads are being formed by hand to avoid the appearance of mass production.
Alibaba is a good place to search for all sorts of new production Chinese & Asian beads. The listings are vast though, so it's sometimes hard to find specific beads.