Stonewear lets you choose between ten beautiful stone and shell textures, including rose quartz, opal, paua shell, marble, jade and granite. Each theme features reflection and shadow effects, with hand and text colours adapted to complement the background.

The clockface possesses an unusual square dial that suits the shape of your Fitbit. To make the time easy to read, the watch's hands change their lengths depending on where they're pointing.

Stonewear displays an activity measure or heart rate, which you can cycle by touching the lower half of the screen. You can set this to show the percentage of your daily goal or maximum heart rate.

If the watch’s hands are blocking your view of the date or activity measure, you can temporarily bring the numbers in front by touching the top half of the screen.

On compatible devices, Stonewear has an always-on display mode.

Cost: $1 USD + tax.