What is a spring lock?
Spring lock (from German spring A spring clasp (or "spring clasp" in English) is a round jewelry clasp that operates using an internal spring mechanism. When asked what a spring clasp is, jewelers describe it as the most common type of fastening for lightweight jewelry.
The design consists of a hollow metal tube coiled into a ring, a hidden coil spring, and a miniature movable tongue. When a finger presses the loop, the tongue moves into the tube, opening a gap for the connecting ring.
This mechanism is machine-made using stamping, ensuring its mass production and affordability. Its light weight and elegant appearance have made it the industry standard for fine gold and silver chains.
Distinctive features
The mechanism is designed exclusively for fine jewelry weighing up to 3–5 grams. When used with massive necklaces or heavy pendants, the spring is subject to excessive stress and quickly fails.
The spring clasp is a non-detachable design. If the internal spring breaks, the case is deformed, or the sliding tongue is lost, the clasp cannot be repaired—jewelers replace it entirely with a new one.
A key design feature is the safety function. The clasp is attached to the chain via a thin connecting ring, which bends when pulled hard. This allows the clasp to slip off, preventing the chain links from breaking and causing neck injury.
How to use
This clasp is ideal for basic thin chains for crosses or pendants, minimalist anklets, and delicate chokers made of small stones.
Due to the small size of the tongue, a spring clasp can be difficult to fasten with one hand. For this reason, it is rarely used on wrist bracelets, preferring instead to use it on neck jewelry, where fastening requires two hands.
When choosing jewelry, it's important to check the smoothness of the tongue. When closed, the sliding part should fit snugly against the ring body without any gaps, otherwise the connecting link of the chain may slip out while wearing.
