There are all sorts of material marketed as Jade. From what I
have read a far bit of Burmese jade (jadeite) makes it down to
Thailand (something to do with Burma or what ever name (Magayr?)
it is going by now being a pretty bizarre military dictatorship -
puts a crimp on regular business). I don’t recall anything called
blue jade though, Sinkankas doesn’t list it either.
You might have to conduct some specific gravity, streak, and
scratch test to confirm it is jadeite. If it is a finished stone
that make the scratch and streak test sort of difficult. Here are
the parameters for jadeite and nephrite. Jadeite- Streak
-white&colourless Moh’s hardness 6-7 S.G. 3.2-3.4 refr. Index
1.66-1.67 should show (hopefully not if a finished stone
finished!) uneven conchoidal fracture. Jadeite comes in a range
of colours, from white to various greens,mauve, yellow, black to
even some nice reds.
Nephrite - Streak - white&colourless H 5-6 S.G 2.9-3.4, refr.
index 1.61, same as jadeite for fracture (source Schumann -
Minerals of the World,Simon & Shuster Gems and Precious stones)
Typically jadeite is quite a tough stone as is nephrite (I have
a chunk I use in the slab saw to wedge odd shape rough in with -
it tapers to a fine edge and hasn’t offered to break yet).
Island Gem and Rock