I can see a few concussions in the future 
Especially as we live on the seventh floor!
Just out of curiosity though isn't mahogany obsidian an oxymoron? Wooden glass stone hmmm.... i'd love to see it 
Collecting obsidian is a minor hobby of mine. The “normal” color, (colour for you, InmemoryofRomeo,;)) is black. But sometimes, there are impurities in the stone that give it different characteristics. I have Rainbow Obsidian, with different colored/coloured parallel lines running through it, Snow Flake Obsidian which is black with white blotches in it, a beautiful blue Japanese Obsidian and of course, the afore mentioned Mahogany Obsidian. The Mahogany Obsidian has reddish-brown impurities that give it its color/colour. I collected the Mahogany on the East side of the Sierra Nevada Mountains. At the time I lived on the West side of the mountains at the 2,000 foot elevation. So, all I had to do drive for six hours, cross over Tioga Pass at 9,000 feet and down to the high plains at 4,000 feet near by Lone Pine and Mono Lake. I loved that area, never got there enough, though for some it might have appeared too stark. And that area had a lot of volcanism which produced Obsidian. BTW, I also have a piece of dino coprolite, (fossilized dino do-do.) Who knows, maybe it came from Pleo's Great, great, great, great, ....great, great.....great, great, great, great Grandfather!

Birds eat stones. This just wasn't the size the gull should be eating. Don't think his gizzard would go for this. 
And if the gull was successful he would need a very tall snorkel in the Bay.
