Nephrite comes from a lot of places: Xinjiang, Russia, Canada, New Zealand, and more.
Jadeite comes, for practical purposes, from one. The overwhelming majority of the world's
commercially significant jadeite is mined in the Hpakant area of Kachin State in northern
Myanmar, and the US Geological Survey tracks the country's jade output on that basis.
A single-source commodity behaves differently from a diversified one. Prices respond to
events in one region rather than to global demand alone, supply is opaque, and the sums
involved are not small. Global Witness, investigating the sector in 2015, valued Myanmar's
jade production at up to US$31 billion in 2014 alone, a figure it put at close to half the
country's official GDP that year, and documented how little of it reached the people living
where it was dug.
For a buyer in the United States there is also a legal history worth knowing, because it
has changed direction three times. Burmese jadeite and rubies were barred from import by
the JADE Act of 2008; the prohibition was removed in 2016 and 2017 as sanctions were wound
down; and after the 2021 coup a new sanctions regime was put in place, targeting designated
entities rather than banning a category of goods by origin. The practical effect is that
origin alone is no longer the test, and provenance questions have moved from customs to the
seller.
None of this makes jade an unethical purchase. It does mean that a dealer who can say
nothing at all about where a stone came from is offering you a smaller amount of
information than the subject requires.
USGS 2019 Minerals Yearbook for Burma; Global Witness, Jade: Myanmar's "Big State Secret"
(2015); the import-prohibition history from the Federal Register.