Opalized fossils and pseudo-fossils
Opal is a spectacular gemstone. Those uncontroversial opening words on the Australia’s National Opal Collection’s website are then followed by:
It is also a dazzling key to Australia’s mysterious past, because buried in the Australian opal fields are fossils of dinosaurs and other strange creatures that lived 110 million years ago, in Early Cretaceous times.1
The Early Cretaceous period is alleged to be from 146 million to 100 million years ago. Fossils, the remains or impressions of living organisms preserved in rocks, can sometimes become opalized. This is a process in which cavities in the fossil, and often the spaces between the organic molecules, become filled with opal (either the precious, dazzlingly colourful variety, turning the fossil into an actual gemstone, or the more common ‘potch’).
The opal can even totally replace the original tissue. Teeth, bones, shells and pine cones have been found beautifully opalized and turned to solid opal. Australia is a ready source of opals, most from the well-known opal mining regions of Coober Pedy and Lightning Ridge.2 One will find opals for sale in most Australian cities.
Unlike other gemstones, opal is not actually a mineral, as it has no crystalline structure. It comprises microscopic spheres of amorphous silica that are arranged in an orderly pattern of closely packed planes. The colours are structural, produced by diffraction (bending of light around an obstacle; the amount of bending depends on wavelength). But how does opal form? It is not magic, as creationist geologist Dr Andrew Snelling explains:
… the ingredients of opal are commonplace stuff. Water in the ground carrying dissolved silica (similar to the glass in windows) is said to have seeped through beds of sand and grit, where the silica particles are deposited in cracks. As the water subsequently evaporated, the silica particles became ‘cemented’ together to form the opal. Light bending around the silica produces the variety of glowing colours.3
Most people think this takes millions of years. However, as mentioned in Dr Snelling’s article in Creation magazine, creationist Dr Len Cram earned his Ph.D. from a secular university for showing in his bush lab that the colours of opalescence appear within weeks, just from the right ‘mix’ of simple ingredients in water. This shows that the silica has already formed the orderly array of spheres characteristic of precious opal. (Dr Cram thinks that cementing them to give a stable gemstone that will not crack on air drying, as even freshly mined opal does on occasion, may take several decades longer.)
Australia is the only country where opalized animal fossils are found.4 The Creation article continues:
Perhaps the most famous example in recent years is ‘Eric’ the pliosaur (a marine reptile), which was the subject of high-profile public fund-raising by The Australian Museum in Sydney in order to purchase these opalized bones from the Coober Pedy miner who found them in 1987. ‘Eric’ is said to be about 100 million years old. No wonder then, in most people’s minds, because of these claimed time scales, and because of the almost universal perception/indoctrination that geological processes are almost always slow and gradual, opals ‘must’ have taken a long time to form in the ground.3
The National Opal Collection website says: “Opalized fossils are rare and precious … even more so because in Australia, it is rare to find fossils of any kind from the time of the dinosaurs.”1
But the opals Len Cram has made in weeks (e.g. Fig. 1) have no distinguishable microscopic differences from gem-quality opal mined at Lightning Ridge. So there is no reason to suppose that opalization in fossils from that alleged age of dinosaurs gives evidence for millions of years of deep time.
Opalized belemnite fossil
I recently photographed several opalized fossils in an opal shop in Adelaide (South Australia), including the beautifully opalized belemnite in Fig. 2.
Belemnites are, like ammonites, extinct cephalopods, a group whose living members include octopuses, cuttlefish, squid, and nautiloids. The shape of belemnites in life was much like a modern squid. This part of the specimen is the most commonly preserved part of the animal, a heavy solid posterior portion of the internal skeleton known as the rostrum.
Opal mineral can contain up to 20% water. There is an obvious connection between dead creatures being fossilized and a lot of water, especially now that it is known opalization can occur over a brief period of time, not millions of years. Such a find presents itself, to one thinking biblically, as evidence of the past global catastrophe that buried vast numbers of creatures, which then fossilized. Some 95% of fossils are, like this belemnite, of marine origin.
So this beautiful specimen speaks of a time of immense upheaval in the world, as do most opals. Len Cram’s experiments indicate that the Australian deposits in which most precious opal is found would have required huge amounts of water and dissolved silicates. Both of these would have been in abundance at the time of the Genesis Flood, yet most who wear these spectacular gems have no idea of their origin.
Pineapples and nuts—opalized non-fossils
The rare ‘opalized pineapple’ shown here on the right was seen in the same opal shop as the belemnite featured in the main text. Despite the resemblance, it never was a pineapple. Such ‘pineapples’ are not fossils but pseudofossils. An original crystalline substance has been replaced by opal, resulting in a cast of the original mineral, giving it its distinctive appearance.
Such casts of an earlier substance are known as pseudomorphs. In this case, the original is thought to have been ikaite (CaCO3·6H2O) after it was first replaced by calcite (CaCO3).1 But ikaite only crystallizes in near-freezing conditions.2 The secular explanation is that these opalized ‘pineapples’ had their origin in a past ice age. But as has been repeatedly shown, the only conditions that can cause a global Ice Age are those prevailing after the world-wide flood in Noah’s day.3 So this aspect of this particular example of opalization has no need for millions of years, either.
The specimen photographed above in the same shop is a rare ‘Yowah nut’, named after the tiny (pop. 142) western Queensland outback town of Yowah. The town is known for its opal fields and this particular type of opal specimen, distinctive to that region.
It is formed when opal infills the central cavity in ironstone concretions. There is no nut involved nor was there ever any living organism.
References and notes
- White Cliffs Opal, whitecliffsopal.com, accessed 24 February 2016.
- Ref. 1, see ‘Opal Pineapple’ under heading ‘Opalised fossils and specimens’..
- What about the Ice Age? Chapter 16 in Batten, D., (Ed.), The Creation Answers Book, Creation Book Publishers, Powder Springs, Georgia, 6th Edn, 2014; creation.com/cab16.
References and notes
- National Opal Collection, nationalopal.com , accessed 24 February 2016. Return to text.
- The Mineral Opal, minerals.net, accessed 24 February 2016. Return to text.
- Snelling, A., Creating opals: Opals in months—not millions of years! Creation 17(1):14–17, December 1994; creation.com/creating-opals. Return to text.
- Animal Species: Umoonasaurus demoscyllus, australianmuseum.net.au , accessed 24 February 2016. Return to text.