Glass Finger

Image: NOAA Office of Ocean Exploration and Research, 2015 Hohonu Moana

Have you heard of the glass delusion?

It was a mental disorder widespread in Europe between the 15th and 17th Centuries. The sufferer believed they were made of glass and might shatter at the slightest touch. Apparently, it was most common among wealthy men, the most famous case being King Charles VI of France who wrapped himself in blankets to cushion a disastrous fall.

Image: NOAA Office of Ocean Exploration and Research, 2015 Hohonu Moana

Some say it might have been an extreme case of social anxiety. People were so terrified of tripping over and embarrassing themselves they figured the WORST would happen. It doesn't get much worse than shattering into a million pieces and having your remains swept up with a dustpan and brush.

It's rather tragic, really. If you want to avoid embarrassing yourself, insisting that you're made of glass and walking around in a suit of blanket armour is not the best way of going about it.

Image: NOAA Office of Ocean Exploration and Research, 2015 Hohonu Moana

All of which is to say that the Glass Finger is not suffering from any delusion. It really is made of glass! Sort of...

The Glass Finger is just one of several species of deep sea sponge in Hexactinellida, the Glass Sponge family.

Image: NOAA Office of Ocean Exploration and Research, 2015 Hohonu Moana

Glass Sponges get their name from their skeleton. Other sponges use calcium carbonate to build up a tough skeleton that keeps them in shape. Without it, they'd just be fleshy puddles on the seabed.

Glass Sponges don't use calcium carbonate. They use silica, the same stuff found in quartz and a major component of most forms of glass.

Image: NOAA Office of Ocean Exploration and Research, 2015 Hohonu Moana

Few Glass Sponges are as beautifully transparent as the Glass Finger, though!

It looks like a crystal palace...

Image: NOAA Office of Ocean Exploration and Research, 2015 Hohonu Moana

Or a crystal tree...

Or maybe a big, crystal stick. Even a stick is beautiful when it's made of crystal.

Image: NOAA Office of Ocean Exploration and Research, 2015 Hohonu Moana

By the 19th Century, the glass delusion had pretty much entirely disappeared. Today it's extraordinarily rare if not entirely extinct.

These days, now that we've discovered bacteria and the like, we're much more likely to go crazy over all the germs floating in the air and brooding on every doorknob, just waiting to infest our bodies and give us interminable flu-like symptoms and who knows what else.

Image: NOAA Office of Ocean Exploration and Research, 2015 Hohonu Moana

The Glass Finger doesn't suffer from that delusion, either.

I don't think putting down a little handkerchief every time it sat on a park bench would have helped.