The Limits of Photography

Biotite on Granite

This is one of my favorite rocks, found - as always - along the shore of Puget Sound. But the reason I love it is not apparent in this photo. The black biotite (mica) crystals that cover the top of this palm sized cobble shimmer with reflected light. It is a layer of crystals, vaguely parallel, but with just enough variation in orientation to catch the light at slightly different angles.

That's a lot of explanation for a simple rock, not well-photographed. I may need to try some other technique to capture the glittering mica crystals. Trust me, it's a beauty....

Discovering Ancient Forests

Petrified Wood, Puget Sound

Every time I open up the tumbler at the end of a polishing cycle, it's like Christmas all over again. Some stones, especially soft sedimentary rocks, never take a polish - but those that do can reveal some stunning patterns and colors. And one thing that I am always happy to see is Petrified Wood. These came out of my tumbler just this morning, pieces of wood I have found along the beaches of Puget Sound over the last few months.

On the beach, they are not always easy to recognize. Although they take a beautiful polish after the fact, they show none of this luster and translucency after they've been tumbled in the surf for a few thousand years. But somehow these caught my eye anyhow - and I'm glad they did.

I have begun to see recurring styles of wood: jet black with tan bark remnants, yellow/orange with strong ring patterns etc.  To me, this suggests a couple of specific (but unknown to me) source locations in the Puget Sound basin.  Logic dictates that the more abundant a certain rock type is, the closer the source. (Or maybe it means that some distant sources are simply more productive)

Wherever the source, they are beautiful.

Things of Beauty

So far, no one has asked me why I collect this stuff (and why our garage is filled with rocks waiting to be polished - or disposed of). Hard to explain really, but let me put it this way. I find the abstract patterns and designs in nature to be stunningly beautiful. It has been argued that nature is ultimately the inspiration for all art; certainly I find the variety of color and design I find on the beach to be as lovely as anything I have ever seen.

This rock, for example, with its subtle shades of color and striking web of black lines, is not so far from classic abstract expressionist art. In fact, I might take up a brush and try painting something like this.  Until then, however, I am content - delighted, in fact - that such beauty exists in so prosaic a setting as the cobble beach below my house.

Washington State Gemstone

I didn't know until recently that petrified wood is Washington State's official gemstone.  It makes sense: we have some wonderful sites for petrified wood around the state, most notably at Ginkgo Petrified Forest State Park above the Columbia River near Vantage. There are many other sites as well, many accessible to the rockhound - and some, memorably, in people's back yards.

But to my knowledge, all of the best sites are scattered around Eastern Washington, many associated with lava flows and ash deposits from Washington's long volcanic history. There are far fewer really good sites on the western side of the Cascades. But for months I have found chunks of this black and brown petrified wood among beach cobbles here in Seattle (See August 25 post). I have found enough of them in fact, of very similar color and composition, that I can only think they are from a single source - somewhere north of here. (But as I have said many times, the glaciers that carved this area could have brought them from hundreds of miles away)

Still, it's always a treat to find them, though in their rough, surf-tumbled state, they are not always easy to recognize...

Home from the East

Opercula

I'm home from Sulawesi, but without any rocks. Most of my time there I was on the coast where everything is limestone and coral rubble. No chance of interesting minerals there. But although I came home without any rocks (and with lighter luggage than usual) I did stumble onto one interesting collectible - the "cat's eye"operculum.  These are the hard "doors" to some species of turban snails and they were common along the shoreline. They are graceful little things and - of course - I brought some home. Probably too soft to polish with stones, but I'll experiment.

Heading East - the FAR East...

Black jasper/agate, Puget Sound

I thought I would post one more local stone (from a Puget Sound beach) before I leave this weekend for Indonesia. It is a highly fractured, but rather lovely, agate-like piece, semi-transparent and hard.

My destination is the island of Sulawesi, and my mission is to document the life history of a unique bird that lives there - the Maleo.  But in the little reading I have done on the island, I have learned that it also has a complex geology including a mix-up of volcanics, and both ocean floor and continental  rocks.

I have no idea whether I'm likely to find any collectible rocks, but as always, I will keep an eye out... Back in a couple weeks.

Patterned Quartzite (?) and Petrified Wood, Olympic Peninsula

I set out this morning to look for a source of variolites, the polka-dotted rock I have posted about in the past, and which probably originates in the basalts of the Crescent Formation on the Olympic Peninsula. I tracked down a couple possible source areas - and found no evidence of variolites. In fact, I didn't find a single one, which is unusual - I have found them in a variety of locations along the Olympic coast. This would suggest that the source is somewhere further west than where I was looking today.  So another expedition is clearly required...

However, I did get some time to poke around the coast near Sequim, where I found - among many other things - these two beach cobbles: a stained quartzite (or Jasper?) and a handsome piece of petrified wood. Not bad for a quick beach walk.