What is the difference between chalcedony and chert

What trips people up sometimes is not realizing how different rocks look from rough to cut and polished. Some rocks, like rhodonite, develop weathering on the outside that totally obscures the colours and designs underneath.

You have a much easier time identifying a polished rock than a rough one. I bet agates and jaspers are all around you too, somewhere. Rivers, lakes, shores are the easiest to hound. Thanks for this post. I just found your site and I am one of those people who stumbles over this question all the time yet but this helps! You might be interested in seeing what Belize has to show for in the way of the quartz family.

The normal dallasites are ubiquitous here as well. Anyone researched these formations for this material and if it is rare? You are commenting using your WordPress. You are commenting using your Google account. You are commenting using your Twitter account. You are commenting using your Facebook account. Notify me of new comments via email. Notify me of new posts via email.

Chalcedony and Chert Chalcedony is a broad term that covers both agates and jaspers. Carcharodontosaurus Teeth. Spinosaurus Teeth. Floating Frame Display Cases. Petrified Wood Bookends. All New Items. Mineral Specimens. Libyan Desert Glass Tektite.

About FossilEra. Where to Find Fossils? Chalcedony is a broad term to describe a microcrystalline form of silica. Agate is any type of chalcedony which is translucent, while jasper is any type of chalcedony which is opaque.

Porcelanite : a siliceous, fine-grained rock. Its texture and fracture behaviour is like that of unvitrified porcelain. Tripolitic chert : a brittle, light-coloured, siliceous, porous sedimentary rock. Mozarkite : is a multicoloured Ordovician Chert.

It easily withstands high polish. Both stones come in the many colors that chalcedonies take, but the most common ones are from white to grey or greyish blue, or from shades of pale brown to almost black. Unfortunately, mineralogists put chalcedony into many categories, leading to plenty of confusion. Another reason people confuse the two stones is that the physical properties of chalcedony occur in narrow ranges. Unlike hardness and specific gravity, chalcedony varies in size; it can range between small grains and large rocks, which weigh several tons.

Agate and chert are both chalcedonies, and the classification of these minerals is a non-standardized horror. Chalcedony is cryptocrystalline silica, which is silicon dioxide in mineral form. Agates and cherts are both chalcedonies.