Serpentine is indeed olivine, and good olivine/serpentine can be
translucent and have a 'ring' like jade but is much softer. It can
be scratched with a pocket knife and even carved with good files,
yet it can also take a good polish using tin oxide on leather at
about 600rpm. There is a deposit just on the edge of Nelson city
that used to be quarried and crushed for use on agricultural land
deficient in magnesium, and used to be used in road making too.
As part of this area traveled South over the millenia (and is still
going South; we are on the edge of an active faultline) one may
pick up matching olivine in the Southern Fiords, such as Poison Bay
which is 300 miles South of Nelson. The Maori knew of it and called
it tangiwai (roughly, funeral tears) but found it far too soft to
use for tools and weapons. They used nephrite jade for those
purposes, which they called pounamu (greenstone)
I am now living life as a scooter-riding, partly lame pedestrian, as
I became convinced that I was a bit of a menace on the roads having
wrecked my car, myself and my wife in the process of this discovery.
It'll come to you all one day!
Cheers for now,
JohnB of Mapua, Nelson NZ