I have seen rough similar to this which was collected many years ago in the states.
This one was sold to me as natural agate from Tibet.
The more I look at it , the more I feel this bead has been coloured since the matrix is slightly more bluish than the rest.
The question is for all three bead sets:
- are they all the same stone type?
- what are they exactly, if agate is there a specific name for this type of agate.
- Am I right to think that 1 & 2 are natural and nr 3 is coloured.
Thank you!!
This stone may very well be dyed but the zoned color is in no way unusual for metamorphic rocks. When certain metamorphic conditions prevail rocks can be in a state of slight melting.In that state it is very common for like minerals in the rock to migrate and aggregate. Metamorphism is usually a partial process which makes ids for geologists a chore. In addition the rock is often subjected to another metamorphosis , usually a down grade metamorphosis which results in zoned crystal aggregations. That phenomena you are seeing in the stone is identical to some zoning. As to the color , blue is a rare calcedony color until recently. Indonesians have found tons of calcedony colored by copper.It is found as replacement of petrified wood, casts, and comes in many shades and is often mixed with opal giving it a slight opal like quality because the intimately mixed opal and calcedony are imiscible, they try to stay segregated and as a segregated medium the light path becomes the type that produces opalescence. Beautiful mystery.
I bought these on a market in China a few weeks ago. I had not seen this color before. They look similar to some of the ones you show.
I did not manage to get he color really right in these pictures, BTW.
They are an agate.
It seems to me they are treated in a variety of ways. I think some of the matrix 'crackle' might be deliberate, and it has been color treated. On one end of the beads, most show a lighter area around the hole.
I suspect these are what is routinely called "sea sediment jasper."
This is a recent Chinese product that has evolved out of the fake-turquoise industry.
As mentioned a few years ago by me, Chinese manufacturers can now take different materials and treat them to become very hard. So hard they seem very stone-like. They even do this to soft non-precious coral (as I demonstrated).
The turquoise fakes are composed from magnesite and reconstructed magnesite, that has been color-enhanced (often just dyed), and hardened. These undergo additional treatments to make them more turquoise-like—including creating "veins" or "matrix," and crackling the material to (supposedly) make the beads seem "old."
In the case of "sea sediment jasper" (as near as I can tell), I believe they are taking reconstructed stone, crushing it to large and small fragments, ** and then reconstructing these pieces by placing them into a melange of reconstructive medium. Then (or somewhere in the process) the resulting material is colored (if it isn't yet, or if additional colors are desired) and it's hardened. Whereupon it has to be exploited like any mineral—being roughed-out, shaped, polished, and drilled. This is something the Chinese excel at performing in mass quantities.
Essentially, this is a strategy someone might come up with in oder to make an imitation of brecciated jasper. So, one could say that "sea sediment jasper" is FAKE BRECCIATED JASPER, that is artificially brecciated, from highly manipulated reconstructed mineral compositions.
The beads seen in replies also look like the "SSJ" beads from China, that are routinely available online. Just a few years ago, we had some dialogues about the fact that Chinese beads are now making their way into West African constructions. This is just another example.
Jamey
There is a company in New Mexico also that is very proficient in the field of reconstructions from real and artificial stones and their products have become quite popular .
These artificial stones have caused confusion in the stone cutting world to a degree and have tremendously misled consumers.
