Almost looks like one of the experimental types with that base glass. I have a series of these ones which look more like snakes and have the dark spiral and dark base glass which can range from an orange line this to almost a grey colour. This marble is very dark in hand, but that Bubbly translucent /almost transparent orange base glass pops right out when backlit. Cork colours appear to be a greyish blue, yellow, auburn, blends, and the orange base Just a touch of pocket wear seen under loupe with a couple dimples