Purple and white in V-shaped bands. Distinctive enough that fakes are rare.
Brazil, Uruguay, Zambia, Madagascar, Arizona
Chevron amethyst is amethyst interlayered with white milky quartz in sharp V or herringbone patterns, formed where growth alternated between iron-rich and iron-poor conditions. The banding is a growth record, and that is exactly why it is hard to imitate: the chevrons have to meet at the crystallographic angles the crystal actually grew at.
Look at where the bands intersect. In genuine material the purple and white zones meet in crisp angular boundaries that repeat consistently across the piece, all obeying the same underlying geometry. Painted, dyed or resin-composite imitations produce bands that wander, vary in width arbitrarily, or meet at inconsistent angles.
Because the material is banded, it also carries the white quartz's properties in the white bands — which is a bonus check. Both the purple and the white must be hardness 7. A soft white band means a composite.
These apply to this model and not to the rest of Amethyst. Work them alongside the maker's general checks, not instead of them.
Genuine growth banding repeats at consistent angles across the whole specimen, because it follows the crystal's own axes. Bands that meander, change angle arbitrarily or fade in and out are not growth zoning.
Both bands are quartz and both must be hardness 7. If the white band takes a knife, the piece is a composite or a dyed soft stone, whatever the purple does.
Inexpensive — a few dollars for tumbled pieces, low tens for a good carved specimen.
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.