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Working with Larimar


#1

I’m looking for anyone with experience working with Larimar (a
variant of blue Pectolite). I have a client who picked up a piece
while in the Dominican Republic on business. It is about 2 1/2 inches
long by about 1 1/2 inches wide. I have seen jewelry made with
Larimar before as well as pictures of it, and this piece seemed to me
to be of a lower quality. The blue was quite pale and there was a
good amount of just white material in the piece, as well as some
black spots which is not unusual given that Larimar comes from
volcanoes.My problem is that as I began to cut and especially when I
put it to my lapidary wheels, it began to fracture badly. My wheels
are 8 inch diamond and even with the gentlest of a touch, they
fractured.When you look at the pieces, you can see what I would call
fracture lines in them. My question is, is this normal for Larimar?
Is it a difficult material to work with? Is there some precaution
that I should have taken,that I didn’t? I work daily with all
qualities of turquoise from hard natural to stabilized, coral, jet,
charoite, pietersite, spiny oyster, etc., and have never had this
problem. I guess what concerns me most is, I don’t want my client to
think me incompetent. I don’t know what he paid for this piece, but
I do know that quality Larimar is not cheap. Any words of wisdom
would be kindly appreciated.

Best wishes,
John Barton


#2

Hello John,

My problem is that as I began to cut and especially when I put it
to my lapidary wheels, it began to fracture badly. My wheels are 8
inch diamond and even with the gentlest of a touch, they
fractured. 

It’s not you. That is the nature of the beast. I immediately went to
my faceting machine and no matter how fine the grit or how slow the
lap turned the stuff still falls apart.

I don't know what he paid for this piece, but I do know that
quality Larimar is not cheap. 

Polished Larimar is not cheap because of the problems you have
noted. Calibration is by luck not good judgement. Getting anything is
good, getting what you planned for is rare. I polish with diamond and
right up until the last stroke the fear of fracture remains constant.
I wish you the best of luck. I won’t attempt this stuff for less than
$50 per stone, get what you get, no complaints accepted, if you
don’t like it get it out of my shop.

Tony.
Anthony Lloyd-Rees.
www.OpalsInTheBag.com
www.TheGemDoctor.com
www.opalsinthebag.com


#3

Hello John

As Anthony Lloyd Reese says, that’s just the way larimar is. My own
experience is the same. The stuff is pectolite in bundle-like
aggregates of aligned fibres. The bundles are what gives it the
tortoise-shell pattern. But it is very prone to breaking along the
fibres no matter how smooth your wheel.

One dodge you might try is to make a cutting doublet. Glue the
preform onto a substrate; cut the stone, then dissolve the glue.
I’ve heard this is how production cutters do it. But that is word of
mouth and I’ve not yet had occasion to try it out myself.

Cheers,
Hans Durstling
Moncton, Canada


#4

Does opticoning of larimar do any good for it’s stability?

Jeanne
www.jeannius.com
www.rhodes-moen.com


#5

Hi John,

I have been working with Larimar for the last while now and it is
not an easy stone to work with. Anthony Lloyd-Rees pretty much said
it all.

Out of every ten stones I cut, four would die in my hands…

I bought $600 worth of top grade material and the better the
material ( that is to say, the most blue) the stronger it is.
However I have not been able to facet a piece yet and I have tried
several times with the best material. Maybe I was just unlucky, but
the darned stuff always expires on the 1200 lap, not the 220 lap as
logic would dictate.

I have also stabilized the material with a little success, by
dunking it in polyester resin and then vacuuming it. Worked so, so,
and I don’t use it in my jewellery because of the treatment.

A while ago someone asked about tumbling Larimar. I took all my
offcuts and low grade pieces and dumped them in my small tumbler
with 120 grit for a couple of days. No problems were encountered. I
did not bother to polish it up, but I have no doubt that Larimar
will polish like any stone of comparable hardness.

The opening page of my website has a piece of Larimar cut in the
shape of the island of St,Maarten, set in a 18ct gold and titanium
composite pendant.To say the least, I sweated blood to finish the
Larimar. Any other questions are welcome.

Cheers, Hans Meevis
http://www.meevis.com


#6

Hi John!

As I recall Larimar (Pectolite) has a hardness of about 3.5 (even
softer than Turquoise) and has a botroidal nature of growth. We have
a lot of pectolite here in the Pacific Northwest and it is pretty
when worked up. If you have a slabbed piece of this material, it
seems that it would make sense to pre-treat the slab–like turquoise
is stabilized–in order to insure a good outcome. Pre-treating may
also enhance the color.

Vi Jones, now busily canning pears, but did finish three jewelry
projects last week, two self made stone intarsia crosses (1 pendant
and 1 bola tie–set in SS) and one hammered SS cross with turquoise
stone for family gifts. They loved them and that is so gratifying.


#7

I haven’t cut that much, perhaps a dozen pieces which I picked up in
the Dominican a couple of years ago. However, I’ve had no problem
with the stuff whatsoever. It does tend to be a bit soft however and
diamond is not, in my opinion the best way to polish it as it tends
to undercut a little. I’d use Linde a on leather for that.

Other than that, I wonder how aggressive your diamond it that tears
it up. I’m guessing the piece you have is unstable to begin with and
in order to be able to cut it you’d need to stabilize it. Of course
then it’s no longer untreated.

Good luck.
Derek


#8

so George…

I purchase some slabs of Larimar last year at the Electric park. I
did not know to ask if it was treated. So my questions are

  1. how can I tell if has been treated?

  2. How does one treat the slab before cutting and polishing?

Thanks in advance Barb

Barbara Smith McLaughlin - Handcrafted Jewelry
PO Box 793, Stratham, NH 03885
www.barbarasmithmclaughlin.com
@Barbara_Smith_McLaug