Dinosaur Fossil Gembone unpolished 5" slab Jurassic Morrison Fm. Utah UT COA5695 for Sale

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Dinosaur Fossil Gembone unpolished 5" slab Jurassic Morrison Fm. Utah UT COA5695 For Sale

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Dinosaur Fossil Gembone unpolished 5" slab Jurassic Morrison Fm. Utah UT COA5695:
$39.95

Welcome to PioneerFossils!

A Certificate ofAuthenticity, which has a photo on it of the exact item you purchased, willaccompany the specimen.

Here is a slab of somewonderful unpolishedhigh-grade Dinosaur Gembone. From a Sauropod.

It is about 5 inches across at the longest measurement (see photos). Using calipers, the thickness is about 6.5 mm. The specimen weighs 4.6 oz. (132 grams). Nice cell walls and great coloration.

The photos of the gembone held in a hand are taken wet, in direct sunlight.

From the MorrisonFormation, probably from Utah along the Utah-Colorado border. From an old collection. These formed during the Jurassic, about 150 million years ago. This is where gembone is found. It is neverCretaceous, and the Morrison Formation (Jurassic) is home to the best gemstone. Most gemstone is from sauropods, thoughAllosaurus, Stegosaurus and a few other species can be found.

Gembone is one ofonly 5 recognized gems from living things. The other are pearl, ammolite, jetand amber. It is made from dinosaur bonethat has agatized, and minerals from groundwater are deposited within the bones,where the marrow used to be. Thetrabeculae, which were the spongy partitions in the bone, form a series ofborders around the colored minerals. The trabeculae can be dark or light, ascan the minerals.

Gembone colorsare many. Most (about 95%) are “earthy” colors, such as brown, greys and tans.However, reds, blues, whites, yellows, oranges, etc., are in a small number ofthem (about 5 % of gemstones). These arethe most popular colors. The mineralscausing these colorations include agate, hematite, iron, pyrite, jasper, marcasite,quartz or other crystal or mineral.

Some gemstoneshave interesting patterns. Sometrabeculae “cell walls” resemble spider webs, and are called spider-webgembone, and sell for a premium. Dark trabeculae is usually desired, as itcontrasts well with the colors of the minerals. “Glassiness” and clarity are also important.

The 1998 rare book, “AMERICAN DINOSAUR The Vanishing of Gemboneby Thomas Helfrich”, accurately predicts the increasing rarity and virtualdisappearance of gembone, we are told.That is exactly what has happened. Top grade gemstone is almostimpossible to find in the wild anymore.

That is because ofthe “perfect storm” of events 35 million years ago in today’s MorrisonFormation that allowed gembone to form. Nowhere else in the world, to ourknowledge, did this happen in exactly the same way. To quote another, The layerson the Colorado Plateau rose up during the Tertiary intrusions, about35,000,000 years ago, when the San Rafael Swell and the La Sal, Henry, andAbajo Mountains were formed. As these ranges were forming, local strata layerswere flooded with silica-rich, superheated groundwater. This provided theappropriate environment to begin the replacement of the calcite in the originalfossils with silicates.

We have heardexcellent gembone has increased many times in value in just the last few years.Gemstonelooks brighter and clearer when it has been polished.

We invite you to visit ourstore. Once inside our store, you willsee about a thousand items for sale, and we hope you will lovethem.We sell items ranging from budgetto superb.

5695 storage QQ