Basic Information
Rock gnomes have a natural inventiveness and hardiness beyond that of other gnomes. Most gnomes are rock gnomes.
Relations of other Races
Despite their varied origins and homes, Forest Gnomes, Rock Gnomes, and Deep Gnomes all get along well with one another, believing that a gnome is a gnome regardless of background, and a gnome is always family.
Physical Appearance
Gnomes are small people with pointed ears and rosy features. Most have thick hair growing atop their feet, arms, and hands.
Rock gnomes have natural coloration, similar to that found on humans.

Racial Traits (Subrace)
Ability Score Increase
Your Constitution score increases by 1.
Artificer's Lore
Whenever you make an Intelligence (History) check related to magical, alchemical, or technological items, you can add twice your proficiency bonus instead of any other proficiency bonus that may apply.
Tinker
You have proficiency with artisan tools (tinker's tools). Using those tools, you can spend 1 hour and 10 gp worth of materials to construct a Tiny clockwork device (AC 5, 1 hp). The device ceases to function after 24 hours (unless you spend 1 hour repairing it to keep the device functioning), or when you use your action to dismantle it; at that time, you can reclaim the materials used to create it. You can have up to three such devices active at a time. When you create a device, choose one of the following options:
Clockwork Toy. This toy is a clockwork animal, monster, or person, such as a frog, mouse, bird, dragon, or soldier. When placed on the ground, the toy moves 5 feet across the ground on each of your turns in a random direction. It makes noises as appropriate to the creature it represents.
Fire Starter. The device produces a miniature flame, which you can use to light a candle, torch, or campfire. Using the device requires your action.
Music Box. When opened, this music box plays a single song at a moderate volume. The box stops playing when it reaches the song's end or when it is closed.
At your DM's discretion, you may make other objects with effects similar in power to these. The Prestidigitation cantrip is a good baseline for such effects.
Myths and Lore
Creation Myth
Prototype created the Deep Gnomes when En was new, hoping to gain knowledge of this new, strange plane which he could use to their advantage. They soon realized, however, that their humanoid creations had the drawback of being independent thinkers. Deciding that En and the Deep Gnomes were an unproductive waste of time and energy, Prototype quickly abandoned them.
After The Lightbringing, Hestia took notice of the abandoned Deep Gnomes, and decided to adopt them as a patron goddess. Fascinated by the kindness and closeness of the small folk, Hestia copied Prototype's designs, creating the Forest Gnomes and Rock Gnomes.