Gold "purity" (or fineness) shows how many parts out of 1000 are pure gold. 585 gold contains 58.5% pure gold (14 karat), while 750 gold contains 75% pure gold (18 karat). The rest is an alloy of other metals (silver, copper, zinc), which gives the jewelry its hardness and color.
Hardness and durability
Counterintuitively, 585 gold is usually more scratch-resistant than 750 gold, precisely because it contains a higher percentage of alloy. That's why wedding rings and everyday rings are often made from 585 — they hold up better to daily wear.
Color
750 gold typically has a richer, warmer color, closer to the "classic" yellow of pure gold. 585 gold can have slightly different shades depending on the alloy — from lighter yellow to rose or white, depending on the added metals.
Price
At the same weight, 750 gold costs noticeably more than 585, because it contains more pure gold. The price difference can be 25-30% or more, depending on the gold market rate.
Which one to choose?
For everyday jewelry (wedding rings, daily-wear rings), 585 gold is the practical choice — durable and more affordable. For special-occasion pieces or gifts, where rich color and purity matter more than wear resistance, 750 gold is an excellent choice.