In more-recent years it has been determined (and I have discussed it multiple times) that"Chinese root amber" actually is found in Borneo. I learned this before 2015, because at that time I hoped to meet a local geologist who might know something about the material, since I could not find any references to it apart from vague Chinese-context remarks. It's a curious thing that nearly no other country or culture has used it in ornamentation (unless this is something so esoteric that it's not common knowledge). I have not yet seen or heard of a Borneo artifact made from this amber--though it would be very surprising if there were not any.

So, a Russian origin (which would be mostly Baltic amber anyway) seems very unlikely.

Also, for the past six years a new Indonesian source of amber, in Sumatra, has been discovered and exploited. Like Borneo root amber, the Sumatran material is probably also Miocene, and from about 40,000,000 years ago. It can be two mottled or mixed-together resinous materials, like Borneo amber--though the conformations are different. The Sumatran sellers are calling this stuff "zebra amber." I was buying Indo-amber (if we may call it that) yearly at Tucson, from the time it was first marketed abroad, over three years. And once online. And, from a Sumatran manufacturer, I have bought a long necklace of "red amber" beads (that is typically a turbid but somewhat translucent orangey color, appearing brown in reflected light). But I have seen specimens that appear to be a more-true-red.