Back then, aquamarine was one of my favourite gems — it still is. Included material has been a perennial too, material such as rutile in quartz (rutilated quartz), gem crystals within gem rough, ‘negative crystals’, and veils. A friend of mine at the time referred to all these inclusions as ‘floors, doors, and windows’ and he was right. Cutting the first ‘window’ on such a piece of rough revealed an absolute treasure-trove of other worlds, hence the naming of this group of gems.
Rather than start another category (as a particular gem can contain both clear and interesting areas within), I’ve taken the liberty to place absolutely eye clean gems here, too.