A London widow, somewhere in the 1880s. The black crepe has been replaced by aubergine and violet after the first mourning phase; in her ear hangs an amethyst in a closed setting, rose-cut diamonds surrounding it. This second phase is called half-mourning — colour is allowed back, provided it is subdued. Amethyst suited it like no other gemstone: dark enough for etiquette, warm enough for the face. It is one of the few gemstones whose social significance we can still decipher when we hold the jewellery in our hands.
Amethyst is the purple variety of quartz, coloured by traces of iron and natural radiation in the Earth's crust. Hardness 7 on the Mohs scale — not as hard as corundum, but tough and suitable for daily wear. The colour ranges from pale lilac to deep purple with a subtle red glow, the 'raspberry flash' that collectors use as an indicator of fine material.
The gemstone in brief
For centuries, amethyst was a prized gemstone in Europe. Bishops and abbots wore it as a sign of spiritual dignity; royalty as a sign of sobriety with status. The Greek a-methystos means 'not-intoxicated' — an amulet against drunkenness, literally carved into wine goblets during the Renaissance.
Until well into the nineteenth century, amethyst was rare enough to be considered a precious gem. This changed with the large Brazilian finds in Minas Gerais and Rio Grande do Sul (1870s–1900s): suddenly so much material flooded the market that the price dropped significantly within a generation. Amethyst shifted from precious to accessible — a shift in image that continues to this day.
Periods in which you will encounter this gemstone
Georgian and early-Victorian work (before 1860) features amethyst as a substantial oval or round cabochon in a closed foil-backed setting, combined with intricate gold or pearl. The colour is usually Siberian or Uralic: deep purple with the red flash. See the Victorian style guide for broader setting conventions.
In the second half of the Victorian period (after 1880), amethyst appears abundantly in half-mourning jewellery — the second phase of mourning where purple, mauve, and grey were permitted. See the mourning jewellery guide. Cluster brooches and drop earrings with amethyst combined with seed pearls or jet black enamel are typical. Snake rings with an amethyst as the headstone also appear.
Art nouveau (1890–1910) embraced amethyst for its soft colour, often in iris-shaped brooches or pendants with flowing plant compositions. See the Art nouveau style guide. Edwardian work uses amethyst in delicate halo mounts. Art deco (1920–1935) rarely places amethyst at the centre — the flat geometry of that period is better suited to corundum; however, it is found in accessory compositions and cocktail rings.
In retro (1935–1950) and 1950s cocktail work, amethyst reappears as a substantial rectangular or oval central gemstone in yellow and rose gold. The colour is usually a brighter purple, partly due to the then-common heat treatment and the dominance of Brazilian material.
Georgian and early-Victorian work (before 1860) features amethyst as a substantial oval or round cabochon in a closed foil-backed setting, combined with intricate gold or pearl.
Old vs. modern
Colour origin is the first distinction. Siberian or Uralic material (roughly pre-1900) displays deep purple with a red flash in warm light and a blue flash in daylight — a bicoloured effect that collectors read as a signature. Brazilian material is usually a more uniform purple, slightly cooler, with less play between day and evening light. Both are period-correct in vintage work; only the perception of value differs.
Colour zoning is a second indication. Natural amethyst often has lighter and darker bands or patches within the same stone, visible when held against white paper. A modern cutter tries to resolve this by orienting the table on the darkest part; an old hand-cut allows the zoning to remain. Extremely uniform, vivid colour without any zoning may indicate hydrothermal synthetic quartz (available commercially since the 1970s) — which falls outside any vintage era.
Recognising heat treatment at a pattern level is difficult, but there are indications. Heated amethyst sometimes loses its red flash and shifts towards a more uniform cool purple; if the stone overshoots during heating, it becomes citrine or prasiolite (green). In vintage work from before 1900, the probability of untreated material is significant; from the retro period onwards, treatment gradually became more common. Certainty can only be provided by a gemmological laboratory.
Cut reveals the period. Old amethysts often have a small table, a deeper pavilion, and manual facet irregularities — similar to the patterns you recognise in the cuts reading guide. Modern stones are machine-identical and optically optimised; they sparkle differently, more busily.
