Friday, October 29, 2010

Maryland's Embarrassing State Gemstone

Six years have passed since then Governor Erlich signed legislation naming "Patuxent River Stone" as Maryland's State Gem. Meanwhile, many who are prominent in state gemological, geological, paleontological and mineralogical circles continue to express outrage. While the stone itself has merits, the grievances focus on a misleading official description of Patuxent River Stone as both agate and dinosaur bone. "An embarrassment to the State of Maryland" is the kindest language I've heard regarding the misrepresentation of a material that is in truth quartzite. Even the Maryland State Archives erroneously describe Patuxent River Stone as "agate, a cryptocrystalline form of quartz."

A look through the microscope at the slab of Patuxent River Stone featured in our title picture makes clear that despite appearances, it is neither agate nor fossilized dinosaur bone. Immediately apparent is an obviously textural rather than cryptocrystalline structure of sandstone metamorphosed into quartzite through tectonic compression.

The official web site (link provided in first paragraph) for this material, which labels it as Patuxent River AGATE, proclaims that a state gemstone should be beautiful, colourful, take a fine polish, be able to be fashioned into jewelry, and very notably be "rare but findable, existing in sufficient quantity to allow for a reasonable source of supply for local artisans." Agatized dinosaur bone is nowhere near that abundant in Maryland if it exists at all. For that matter, as the person responsible for the Maryland Minerals web site, I've never seen any kind of agate that was collected in Maryland and am unaware of any literature regarding its occurrence in the state, except in conjunction with "Patuxent River Stone."

To help me research this post, a prominent local gem cutter drove me to a pebbly stream not far from I-95 in White Marsh. Twenty years ago, most of this area consisted of sand pits where quartzite pebbles were extensively quarried for construction material. White Marsh lies on the Arundel formation, which runs diagonally through the center of Maryland extending even to the Eastern Shore. Dinosaur fossils have been reported in Arundel Formation deposits, but they consist of neither agate nor quartzite.

We crawled about the stream bed on hands and knees looking for
colourful quartzite pebbles. They were scarce enough that searching for them proved an enjoyable but very easy challenge. Pictured at right are a few that we picked up. A presence of iron speaks for their colour, and no doubt they would polish beautifully.

Meanwhile, Maryland, unlike numerous other states, does not have a State Mineral or a State Rock. Since Maryland was once the world's second leading producer of chromium, a good choice for State Mineral could be chromite. Yet, what better choice for a Maryland State Rock than quartzite? And who is to say that quartzite should not qualify as the State gem if sufficiently graded for colour?

So why does our State Gem continue to be incorrectly touted as agatized dinosaur bone? " Those not into the hobbies could care less," my gem cutter friend replied." Then, requesting for political reasons that I not use his name, he added: "To guys like you and me it's an embarrassment, and even worse, you've got all this false information being passed on to school kids."


  1. Maybe calling the quartzite 'dinosaur bone' or 'agate', is in some ways more attention grabbing lifting the perceived profile of the rock. Perhaps?

  2. Fred Ward should hang his head in shame for this embarrassment to the state of Maryland :(

  3. Lapidary Journal hyped this one & need's to do a retraction.No such thing as Patuxent River Agate. :(

  4. Not to mention that even if it were Agate, Dino Bone or anything else like it, it still wouldn't have enough economic feasibility to be considered a State Mineral/Gemstone, as according to the official website.

    Somewhere in Maryland, I'm sure there has to be a reasonable deposit of a viable semiprecious/precious gemstone, I mean come on, we're talking about trillions of tons of Earth here. We may not be the biggest state but I'm sure we could find something other than "Patuxent River Agate."