I noticed a patch of darker sand up at the high tide cusp.Taking a closer look I saw that it was black, unlike anything I've seen here. My first thought was that it was polluted sand dredged from the channel, which idea a lifeguard corroborated. As I thought about it, though, this didn't make much sense. I picked up a handful and washed it in the ocean. Nothing happened. It didn't feel oily, it didn't float, it didn't dissolve. I found a cup and took some home for a closer look.
Later on I went back for more. About halfway back home from that trip I began to feel the weight. This stuff is more dense than the common sand. I did some research.
Magnetite forms in swamps. Ballona Creek used to be a swamp. How this small patch of magnetite ended up here I don't know.
When I took some macro photos I got a surprise. Most of it is black and fine, but there are other characteristic grains mixed in, such as garnet. What a fascinating sculpture could be made with this sand.
This sequence of photos zooms in step by step. The first one is the full frame scaled to the blog dimensions. These first three were shot as an experiment on a cloudy day using manual white balance from a grey card..
Click on any image to see it full size.
The image below has been cropped to about half the original frame, then scaled to the blog to get in closer.
This image is at maximum size, cropped to actual pixels. The area is about 15mm wide.
This maximum magnification image was shot earlier under sunlight with a diffuser.
Not being all that happy with the photos taken under cloudy light, I took some more today. The day was clear, just a high white haze, so I used a diffuser to cut down the specular highlights. The original is 6720 pixels wide; I cropped that to 3360 and then scaled to 1536 and used unsharp mask.