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Northern California Jade


#1

Does anyone know what types of jade occurs naturally in Northern
California? Thanks, Soeun


#2

Most of the jade in California is nephrite jade.

Cheers
Virginia Lyond


#3

That would typically be the nephrite variety… dark green to almost
black. Often occurring in massive boulders and alluvial deposits. Also
occurring rarely is a prized form called botroydal (sp?) jade, which
has a bumpy, or bubbly surface. As far as I know, it only comes
(came?) from one locality and may be “tapped out.” Lapidary Journal
had an article (or two) about this rare jade a few years ago.

Hope this helps!

Dave
Dave Sebaste
Sebaste Studio and
Carolina Artisans’ Gallery
Charlotte, NC (USA)
dave@sebaste.com


#4

Dear Soeun, The best known deposits of Jade occur throughout the
Coast Ranges beginning just north of San Simeon and continue all the
way to the Oregon Border. The southernmost occurrences, frequently
known as “Monterrey Jade”, are Nephrite and the overall quality is
very low. Finding a piece on the beaches where it is known to occur is
extremely difficult and, technically, off limits ,as that stretch of
the coast has been set aside as a marine preserve. Black and dark
green Jade in both Nephrite and Jadeite occur on Clear Creek near the
Benitoite deposits. Probably the most prolific source of both
Nephrite and Jadeite occurs near Covelo, just above Santa Rosa. This
latter deposit has been mined sporadically for over a century and
produces large boulders of somewhat off color jade in a variety of
shades and patterns. I have a quantity of this Jade, including that
which I call “Flower Jade” because of it’s unusual pattern. Farther
north, the Trinity River has been known to produce Jade, but is
probably better known for it’s deposits of “California Jade” which is
not Jade at all. It is an intimate mixture of Idocrase and white
garnet which is actually harder than jade and takes a fine polish. I
prefer it to any of the California true jades in that it has a more
distinctive coloration and pattern and can be quite translucent. It
too is quite tough…easily comparable to jade. It should be noted that
throughout the range of California Jade occurrences two other stones
nearly always accompany the jade deposits and can easily be confused
therewith…they are Serpentine and green Chert. The Serpentine is
softer than Jade and the Chert is harder. Otherwise they are virtually
indistinguishable with Jade. Happy hunting!

Ron at Mills Gem, Los Osos, CA.


#5

Hi, all- While most Northern California Jade may be nephrite, the Chan
Jade Mine in Northern California did produce some nice, apple-green
jadeite. I don’t know if it is played out or not-- I visited the mine
when I was a kid, roughly 30 years ago.

Lee Einer


#6

Offhand, I have seen black jade, green jade (some of it beautifully
translucent) a mottled green and white, and a botroidal jade from
Northern California. There is also a black jade with puffs of
magnetite crystals in it. They polish the jade, then electroplate
with gold. Just the magnetite crystals pick up the gold. It is quite
stunning.

Rose Alene McArthur