Kasumiga pearls fw pearls from Japan


Well-known member
Dec 11, 2004
I searched for the words Kasumi and Kasumiga on this forum before I started this thread- couldn't find anything so here goes what i have found out. Kenji-please comment!

Kasumiga pearls are from a lake in Japan by the same name. They are freshwater pearls that areproduced by a hybrid clam. Please go to this link for a description http://www.imperial-deltah.com/news2/kasumiga_pearls.htm

a really fascinating thing about these pearls besides their huge size and beauty is that they are nucleated with thinly nacred akoya pearls! That is, clam shell beads were put into the akoya as usual, then when they were removed they were actually drillled, then rejected for sale I presume, then put into the freshwater mussel!

(Remember, I asked in another post if fw pearls could be used to nucleate Akoyas to produce a solid nacre akoya. Apparently not, but here is the opposite. I believe the company is disclosing this now, if not before, and I think it is probably the best way to get pearls so large.)

(this is a quote of the online summary by the GIA)
Gem News contributing editor Dr. Henry Hanni of the SSEF Swiss Gemmological Institute, recently examined some attractive Japanese freshwater cultured pearls called Kasumiga after the pearl-culturing region of Lake Kasumiga, north of Tokyo. The three 40-cm-long strands consisted of approximately 40 pearls each, with diameters ranging from 9 to 13 mm. X-radiographs revealed the presence of two drill holes in each pearl at a random orientation to each other. Gems & Gemology previously reported such features in Japanese freshwater cultured pearls nearly 40 years ago (see R. Crowningshield, "Fresh-water cultured pearls," Spring 1962, pp. 259-273).

With the client's permission, half of one cultured pearl was ground away and the surface polished. The bead nucleus was covered by a very thin (0.2 mm) overgrowth of nacre, which was separated by a slight gap from a much thicker (>2 mm) layer of freshwater nacre. An energy-dispersive X-ray fluorescence analysis of the pearl's surface showed an abundance of manganese, thereby confirming the freshwater origin of the outer nacre layer. It appears, then, that drilled low-grade Akoya (saltwater) cultured pearls were used as bead material for these Kasumiga freshwater cultured pearls, which are said to be grown in a Hyriopsis schlegeli x Anadonta plicata hybrid mussel. The result is freshwater cultured pearls of remarkable diameter with thick nacre layers and appealing surface quality.

More information and photos of these Kasumiga cultured pearls will appear in the upcoming Summer 2000 issue of Gems & Gemology.

To reserve your copy, or to subscribe, contact the Subscriptions Manager, Debbie Ortiz [mailto:dortiz@gia.edu], or call toll-free 800-421-7250 ext. 7142. Outside the US and Canada, call 760-603-4000 ext. 7142. Visit G&G online.

Here is a link to a strand being sold on ebay. I emailed the seller and asked permission to post the actual picture here as well.
There is a bit more information about these pearls in this thread. I think it was one of the first threads on this forum, at least the first one I posted to I think.

It surprises me that Akoya pearls are being used as a nucleus. Especially 'drilled' Akoya pearls. This sounds to me more than anything else that they used them when they ran out of their typical nucleation bead.

The whole idea of nucleating freshwater pearls I am still not very comfortable with. I know that the resulting pearls are much larger and rounder, but this can still be obtained via the conventional mantle method.

By the way, I have heard from the Tsuji province area that a newest crop of freshwater pearls are really amazing. Round and with luster like the Akoya. Has anyone else heard? I have not seen them yet but preliminary pricing is only about 15% over average.
Hi Kenji
Thanks. I read the thread.

The thing I love about FW is that they are solid nacre. I understand it takes 5 or more years to get fw pearls 10mm and over? Since America likes bigger and cheaper, I can see there would be a market for bead nucleated giant fw pearls.

I notice jshepherd reports he saw a Kasumiga strand for $3000 and thought that a Chinese equivalent size he owned for $300 was the better strand and the better deal. Sounds like the Lake Kasamiguara folks are in a stiff learning curve!
I will get to view the $3,000 + Carolyn Ehret strand at the Gem show this year and I hope to review it here.
BTW I did get permission to post a picture of it here, but the link has about 4 pictures of it.


  • 35_1_b.jpeg
    19.8 KB · Views: 120
Last edited:
You are right about the 'bigger the better' for freshwater pearls. Nucleated freshwater pearls do increase the production of these. But the freshwater production technology is getting so much better these days that large pearls of equivalent quality to smaller 6-7mm pearls (top-line) are being produced.

The problem that I have with nucleating freshwater pearls is for a couple of reasons. First, if the pearls are nucleated with a substance other than another freshwater pearl, the freshwater pearls are no longer solid nacre. This is the draw of freshwaters for so many people. If the pearls are nucleated with pearls, how do we know? These pearls would appear to be of the high-value solid nacre, large round pearls. But they would be deceiving if the seller did not divulge their production. Because these pearls are coming from China, and will pass through a myriad of different hands, when these pearls become cheaper to produce I believe many, many of these pearls will unknowingly exchange hands.

I guess the best thing to do is wait and see. There is one large company in China that is producing a lot of these pearls, and the last I heard they are starting to have a pretty high success rate. I am not yet sure of market price differentiation between them and the solely mantle-tissue nucleated pearls.
Kenji said:
By the way, I have heard from the Tsuji province area that a newest crop of freshwater pearls are really amazing. Round and with luster like the Akoya. Has anyone else heard? I have not seen them yet but preliminary pricing is only about 15% over average.

The pearls are amazing, Kenji! I have just received a 2-kilo sample of them. On my way back from Asia I met with a farm-coop head who brought me some of their new samples. They were under 1K per kilo, and I was able to take them with selection. I just got back yesterday and under first comparison to the best we have been able to produce in the past the pearls are amazing. I am now scheduled to go out to Zhuji to visit the group in March. They have about a 40-day lead time at this point, and with the size and the farm they have told me they can produce about 60-Kilo per harvest at this point. I imagine this is embellished a bit, but even if it is only 40-Kilo I plan to take it all at this point.
Last edited:
Hi Guys,
I am a newbie here and am impressed by all the knowledge you all have. I am trying to figure out the value of a mixed Tahitian and Kasumi pearl (9-11mm) necklace and learn about Kasumiga and Edison pearls. Can use any help I can get. Thanks.


  • kasumi.JPG
    51.9 KB · Views: 129
Hi there Bpaul, and welcome to our pearl loving forum....wow...that is an unusual pearl necklace.
I would value each pearl individually and then look at how well matched the necklace is, how well it hangs, and then give it a value.
Is someone selling you this piece? I don't see any obvious Kasumi pearls there...they are my favorite FWP and I cannot ID any in that photo.
To me it looks like a freshwater pearl necklace, the dark pearls look dyed to me. I could be wrong...the photo doesn't offer too much detail.
Hi bpaul, I agree with Douglas on this. I see nothing to indicate genuine Kasumi pearls nor Tahitian pearls. Now both come in a very wide range of looks, and this is just one photo so ... do you have any documentation of the pearl types, source etc.? Possibly any additional photos and closeups of pearls? Welcome to the forum :)