The Badakhshan material — the deepest blue, and the standard the rest is measured against.
Badakhshan, Afghanistan — the same mines for six thousand years — with Chile and Siberia
The Sar-e-Sang deposits in Badakhshan have produced the world's finest lapis continuously for around six thousand years, and the material remains the benchmark. Its blue is deeper and more violet than Chilean or Siberian lapis, and the best of it carries very little calcite.
Grading is straightforward once you know what to look at, and it is mostly subtractive. Calcite is the enemy: white veining and patches drop the grade quickly, and heavily calcitic material reads pale and mottled. Pyrite is desirable in moderation — finely dispersed gold speckling is part of the appeal and evidence of authenticity — but coarse pyrite lumps and dense pyrite zones reduce value.
Because the good grades are expensive, Afghan lapis is where dye turns up as an enhancement of real stone rather than as a substitute for it: pale calcitic lapis dyed to deepen the blue. Look at the calcite veins specifically, because they absorb dye differently from the lazurite and will read blue where they should read white.
These apply to this model and not to the rest of Lapis Lazuli. Work them alongside the maker's general checks, not instead of them.
On dyed lapis the calcite veining takes up dye and reads blue or blue-grey instead of white. Genuine untreated material keeps a clear colour distinction between the blue lazurite and the white calcite.
Value falls with visible white. Fine Afghan material is deep violet-blue with little or no calcite; mottled pale stone with white patches is a lower grade whatever the seller calls it.
The premium grade. Fine cabochons run hundreds of dollars; top rough is priced by the gram.
An orientation for honest, unrestored condition — never an appraisal, and never a quotation.
Lovenhall StoneThe tests tell you what it is. The instrument reads a photograph and offers a name to start from — then hands you back to the tile and the coin, which are what settle it.