The woman, named as Jenjira Noofoon, 23, suffered bruises and scraped her elbows and knees while her son, Chanathip Somjit, was slightly injured.
Fortunately, the gold necklace snapped and fell to the road. The pillion rider responsible didn’t pick it up but sped off.
She said she was riding home with her son when she noticed a motorcycle with two men trailing behind her.
She was about to stop in front of a building to seek help when the pillion rider snatched her necklace, sending the two of them and the bike crashing to the ground.
Police will check footage from security cameras to try to catch the two men.