Tuesday, December 2, 2008

It's an Oily Frog !

Let's have a fun look at some of the more unusual gems and minerals that can be found in our world!

At the International School of Gemology (ISG) study is done on specimens rather than by pictures from a textbook. This allows the students to learn more about all of the variables that gemstone properties can offer, rather than teaching a simple listing out of a textbook. To do this the ISG has collected as many gems and mineral specimens as can be found, bought, begged, borrowed or get donated.

Occasionally the finds are just so unique that they sort of defy explanation. And with so many students and friends in so many places world wide, the ISG has assembled one of the most unique collections of weird and unusual gems and minerals that you will find anywhere. This particular stone was donated by Trent at BKK Gemstones, Thailand.

This is a piece of Enhydro Quartz.

The fact that quartz crystals often form in hydrothermal intrusions into existing rock makes it no surprise that there are a lot of weird inclusions to be found in most quartz crystals. But few are stranger than finding Light Sweet Crude Oil inside a quartz crystal. But that is exactly what we have below. This is an enhydro quartz crystal that actually contains far more than first meets the eye. Let’s look at just a few of the unusual features in this particular specimen.

If you look below you see a fairly large pocket of petroleum inside this quartz crystal. This occurred due to the petroleum existing in the hydrothermal intrusion where the quartz crystal formed. As the hot water environment started to cool and the quartz crystal began to grow, the petroleum that was in the hot water was simply engulfed inside the crystal as it grew, leaving pockets of petroleum with gas bubbles inside the cavities of the quartz crystal. But here is where it starts getting weird.

Below you see a formation that has a lot going on with it. Not only do you have a spike looking formation of light and dark petroleum, you also have a lot of twinned crystals. Twinning is when two or more crystals grow in the same dimensional space. In other words, the molecules of the quartz are so tiny and far apart that you can actually have two or more quartz crystals growing within the same place, inside each other. This is what you see below with the many points sticking up to the left of the oil spike. These are simply a whole row of tiny petroleum filled quartz crystals that have all grown inside the larger host crystal. It is actually possible to have scores of crystals growing inside each other due to twinning.

Sometimes these twinned crystals are not full formations, but are sort of ghosts of crystals. What we appropriately call phantoms. A phantom crystal is one that is actually present, but you don’t really see the complete formation because it’s sort of a….well, a phantom. At left you see a phantom crystal that is partially visible due to a cavity that contains water. This water is millions of years old and was inside this phantom crystal when the larger host crystal simply engulfed it during formation. Sort of a "now you see me, now you don’t," looking formation.

But here is where it really gets fun! Below you see a 10x image of this crystal photographed from one very special direction. You can see the blue and yellow colors of the petroleum filled cavities inside the crystal. But WAIT!
What is that? Is that a FROG? An OILY FROG? It sure looks like it !

One of the most fun aspects of crystal study is just how weird some of the inclusions can be. And just how many people can see images in the inclusions….sort of like seeing shapes in the clouds in the sky. In imaging what this crystal looks like, this frog jumped out like a……well, a frog! No, no, no. It’s not a real frog. Just a really frog looking petroleum filled cavity.
If one gets a chance to go to the Tucson GemFair, these are also the kinds of unique items that sometimes pop out at you as you look through the thousands of rocks, stones, gemstones and minerals that are for sale all over Tucson.
Thanks to the ISG for pictures and information on this quartz.