According to TheSaleRoom.com:
Amber has joined jade, ivory, coral and rhinoceros horn among the list of much-revered materials that convey meaning and great status in Chinese culture.
The past 12 months, in which an amber necklace has moved from £200 to £2000 or more has been a steep learning curve for many in the jewellery trade
Amber beads (most are used to make strings of prayer beads) are assessed not just in terms of colour and size but also by density, opacity and the degree of enhancement.
In short, much of what passes for amber on the market has been subject to thermal modification (or is in fact Bakelite). Even bonded amber, that combines pieces of natural amber with a colourless binding agent, behaves in much the same way as pure amber under standard scratch tests so a familiarity with the appearance and weight of a good stone is everything.
Mallams auctioneers recent sales in Oxford and Cheltenham highlighted what buyers go for. One Far Eastern buyer paid £4600 apiece for two strings, both egg yolk to butterscotch in colour, largely opaque and showing little sign of enhancement. Contrast this with the much lower sums realised for necklaces made from reconstituted stone.