Fashion house Hermés revealed a new watch this spring. What makes it unusual? Well, the trend for watch faces to display a bit of otherworldly detritus is of course familiar to anyone who closely follows the spinning world of horology and the details of its revolutions. But Hermés goes one better: different versions of their Arceau L’Heure De La Lune might contain cosmic flak from one of two sources: our moon and Mars proper.

The complication’s a beaut, and offers wearers two distinctive moon phases, one for each hemisphere’s perspective; the design artfully places date and time sections in cycle so that they indicate the moon phase from each hemisphere.

Apart from containing a bit of lunar or Martian rock, materials in the watches include Lapis Lazuli and Blue Pearl. Straps in Black or Veronese Green alligator, matte finish, complete the look. The Arceau L’Heure De La Lune watches are priced a little north of $50K.