Geology and gemstones: Sunday Stamps

The challenge this week on Viridian's Sunday Stamps was to share a stamp featuring something related to geology. I get pretty excited about rocks these days, so I thought this was quite a wonderful, broad topic. Australia has issued several stamps featuring Uluru (formerly Ayers Rock), which is arguably the country's most famous geological marvel. A sandstone monolith, that turns red at dawn and dusk, Uluru is magnificent.

However, given the scope and possibilities for the theme 'geology' I was hoping that I could come up with something a little bit more exciting than the standard Uluru stamps. (That said, there is nothing 'standard' about Uluru itself. It is an awe-inspiring and magical place, and it deserves its iconic status.)

Anyhow, it turns out we don't celebrate rocks (or geology) enough in our stamps issues. I wanted to find a cool stamp with some sort of graphic representation of tectonic plates or volcanic eruptions, or something. But no. What I did find was opals and gemstones. Sort of cool, but not earth-moving, geological-time encapsulating, rock strata-depicting, mind-blowing cool. Just 'reasonably-pretty' kind of cool.

These stamps featuring the opals were issued in 1995 and were the first 'holographic' stamps issued by Australia Post. I was worried that opals wouldn't fit with the geological theme if they are minerals and not strictly speaking rocks, but it turns out they are actually classified as 'mineraloids.' And according to that most reliable source, Wikipedia, they can be found in the fissures of almost any rock.

My scientific education is sorely lacking, but from what I gather minerals are not rocks. Rocks are composed of minerals. So therefore it is fine to include opals in a post about geology, which in part is about rocks (but is not the study of rocks, because that is petrology).

Anyhow, moving right along. Opals are also Australia's national gemstone. The first time opals featured on a stamp was in 1973 when the 8c opal stamp was part of a definitive issue, which combined the bizarrely unrelated topics of 'gemstones and marine life'.

I haven't heard of chrysoprase before, but it looks a hell of a lot like Kryptonite, don't you think? Gemstones are basically pretty minerals. The earth is composed of rocks, which are composed of minerals; and whilst petrologists study rocks, and mineralogists study minerals, geologists study the earth. Minerals are cool, but volcanoes and tectonic plates are cooler. The end.