Amethyst frequently grows in cavities in volcanic rock. The crystals stand perpendicular to a base of agate or chalcedony — the pale rim visible on many druses is exactly that layer.
Colour can vary within a single piece. Zoning is not a flaw but evidence of natural growth. Be cautious with unusually even, very intense tones — there it is worth asking whether the piece has been treated.
Large druses are recovered whole and worked only at the cut edge. The less trimming, the better the grown contour is preserved — an essential criterion for collector pieces.
