I work some with Larimar.
I cut it with a diamond blade on the hanging motor or diamond
slabbing machine. Then if you want to polish small carved pieces, I
grind the most off with a Mizzy wheel and then to finer diamond
wheels/burrs. The stuff takes a polish really easy. I use a sanding
mandrel with 220 grit sand paper, then to 1200 grit and then
polishing paper. That gives it a good bright shine. Then I use
50,000 grit diamond mixed with olive oil on little a felt buff to
bring it up to 'water polish'. The stuff is easy to work and has got
the same feel and easiness as opal. It can be put into rings and
those pieces should be handled the same as say, a Tanzanite ring.
Living in the Caribbean, I love this material, since the very best
quality has the same color as the sea outside my workshop. Keep in
mind the old saying concerning any material, namely, rubbish in,
rubbish out! Don't work in lousy material if you can.
Tumbling won't be a problem, if care is taken. Larimar has a
tendency to split along the white/blue lines but I figure that if it
split during cutting and polishing, that's good because better
sooner than later. Within reason, I have not found it to be heat
sensitive but while the heavy cutting or grinding takes place, it is
quite shock sensitive. That is good, because I want to subject my
work to extremes before I sell it. I have faceted some material for
fun and I used a phenolic lap with Linde A. Without having tried it,
I'm sure cerium oxide or diamond would work as well on a lap.
Good quality material is not cheap, and I find it surprising that it
is often set into badly made silver jewellery .I only set it in 18ct
gold. For some pictures of finished work, go to my website and they
on the first page after the enter button.
Cheers, Hans Meevis