Jewellery terminology describes measurable material facts, and knowing what the terms mean explains why some pieces last decades and others discolour within weeks.
Gold and karat
Pure gold is twenty-four karat and is too soft for most jewellery — it deforms and scratches readily.
Alloying with other metals adds hardness. Eighteen karat is seventy-five percent gold, fourteen karat is around fifty-eight percent, nine karat around thirty-seven.
Lower karat means harder and more durable, and more of the alloy metals, which affects colour and tarnish behaviour.
Which means the highest karat is not the best choice for a ring worn daily, and this is genuinely counter-intuitive to most buyers.
Gold colours
Determined entirely by what the gold is alloyed with.
Yellow gold uses silver and copper. Rose gold uses more copper. White gold uses palladium, nickel or silver.
White gold is generally rhodium plated to achieve a bright white, because the underlying alloy has a slightly warm tone.
That plating wears, revealing the warmer colour underneath, and replating is a routine maintenance job that buyers are rarely told about.
Nickel in white gold alloys is a common contact allergen, and nickel-free alloys are available and worth asking about.
Plating terminology
The area where the terms are most precise and most ignored.
Gold plated means a thin layer applied electrolytically, measured in microns, and it wears through with use.
Gold filled means a substantially thicker layer mechanically bonded, with a minimum weight proportion specified by regulation, and it lasts far longer.
Vermeil means gold over sterling silver, with minimum thickness and purity requirements in some jurisdictions.
Solid gold means the item is gold alloy throughout.
The price differences track these directly, and the terms are used loosely by sellers who are not required to be precise.
Silver
Sterling silver is ninety-two and a half percent silver, alloyed usually with copper.
It tarnishes, which is a surface reaction with sulphur compounds in air and on skin, and it is removable rather than damage.
Argentium and similar modern alloys substitute germanium for some copper and tarnish far less.
Storing silver in a sealed bag with an anti-tarnish strip prevents most of it, and wearing it regularly actually helps since skin contact removes early tarnish.
Platinum
Denser, more expensive, and it behaves differently from gold when scratched.
Gold loses material when scratched. Platinum displaces it, forming a raised edge, which means the metal is not lost and develops a patina rather than wearing thin.
Which makes it the most durable choice for settings holding stones, and it is why it is used for that despite the cost.
Stainless steel and titanium
Both durable, both inexpensive relative to precious metals, and both essentially unresizable.
Which matters for rings, since finger size changes with temperature, weight and age.
A ring that cannot be resized is a ring that will eventually not fit, and this is worth knowing before buying.
Hallmarks
In jurisdictions with hallmarking requirements, precious metal items carry marks indicating fineness and, frequently, the assay office and a date letter.
Which provides independent verification of the metal content rather than relying on the seller.
Where hallmarking is not compulsory, stamps indicating fineness are applied by the manufacturer and are not independently verified.
Practical care
Remove rings for anything involving impact, chemicals or hand cream, all of which do more damage than people expect.
Chlorine attacks gold alloys, particularly lower karat, which is why swimming pools damage jewellery.
Have settings checked periodically, since stones are lost when claws wear rather than suddenly, and the wear is visible under magnification long before failure.
That check is usually free and it is the single most valuable maintenance there is.
Stone settings
Where the practical durability of a piece is determined.
Prong settings hold a stone with metal claws, maximising light entry and exposing the stone to knocks.
Bezel settings surround the stone with a metal rim, which is far more secure and shows less of the stone.
Pavé and channel settings hold many small stones, and losing one is common and repairable.
For anything worn daily, a lower profile and a more enclosing setting will survive considerably better, and the aesthetic preference generally runs the other way.
Stone hardness
Measured on a comparative scale, and it determines what survives daily wear.
Diamond, sapphire and ruby are hard enough for everyday rings.
Emerald is brittle despite reasonable hardness, and frequently contains fractures that make it fragile.
Opal, pearl and turquoise are soft and porous, damaged by chemicals, cosmetics and even by drying out.
Which means the stone determines the wearing pattern more than the setting does.
Treatments and disclosure
Most coloured stones on the market are treated in some way — heat, fracture filling, irradiation, dyeing.
Treatment is normal, and it should be disclosed, and it affects both value and care requirements.
Fracture-filled stones can be damaged by ultrasonic cleaning and by heat from jewellery repairs, which is why disclosure matters practically and not just commercially.