#glendonite

[emeraldcityminerals]

A pseudomorph specimen of the so-called "glendonites" from the White Sea, Russia. These specimens start out as ikaite (calcite but with extra water molecules). When ikaite reaches a temperature above 8°C (46°F), it changes/morphs into calcite. Ikaite is currently a contestant in the Twitter @Mineralcup (March Madness brackets for mineral nerds). 

[drrockclub]

Glendonite star fossil

This fossil is not of an animal, but a mineral. When sea water temperature at the seafloor drops below ~4°C/39°F a carbonate mineral called ikaite will start to precipitate and grow forming bizarre shapes. Even though the original mineral will dissolve once it is buried, other diagenetic minerals will replace its form, making a glendonite.

Gledonite/Ikaite and its specific forming conditions allow geologist to approximate climatic conditions for the time period captured by the rocks in which this mineral is found.

Thanks to the flat exposure on the rock platform, we can appreciate this nature’s creativity.

Example from the south coast NSW, Australia.

[crystalguidance]

Today's featured stone is...GLENDONITE! Glendonite is the name given to a pseudomorphic mineral that has formed when the hydrous calcium carbonate of Ikaite loses its water or hydrous content and is thus transformed into the calcium carbonate mineral known as Calcite. The newly formed crystal retains the star like clustered shape of the original Ikaite. The color of this mineral is light to mid brown in tone. The frequency of Glendonite connects to all the chakras. It opens and harmonizes all of the chakras aligning one energetically. It stimulates the third eye, crown and upper transpersonal chakras so that one’s consciousness is open to the higher dimensional frequencies. It helps one with one’s inner vision and psychic abilities. The energy of Glendonite helps one to transmute old energetic patterns that are no longer serving one, so that one can transform one’s life to reflect one’s truth. Info source: soulfulcrystals .co .uk Photo source: mineralienatlas .de #CrystalGuidance #StitchesAndStonesKC #shopify #forsale #crystalsforsale #dailyfeature #crystals #stones #stone #rocks #gemstones #crystalsofinstagram #crystaloftheday #featuredcrystal #healingcrystals #crystalhealing #metaphysicalproperties #crystalproperties #Glendonite https://www.instagram.com/p/Bslsu0yjaOU/?utm_source=ig_tumblr_share&igshid=7y1emyvz3t4j

[drrockclub]

Not a bone, not a dinosaur!

It is not a fossil bone, and it is not a dinosaur footprint either. This is a glendonite! It is a relic mineral that once grew at the bottom of the ocean which ended up being fossilized. When water at the bottom of the ocean or sea reaches near freezing temperatures, a particular type of carbonate mineral (type mineral that shells are made of) starts to form, usually taking shape of spires and pyramid-like forms which is called an Ikaite. It is a soft mineral and can break or dissolve easily, but if it ends up being buried, it can be fossilized to form the glendonite. This means that other minerals will replace it, while maintaining the original form of the mineral Ikaite.

Glendonites are used by geologists and palaeontologists to infer glacial conditions or near polar location at the time of sedimentation due to its exclusive formation at low temperatures.

Example from Wollongong, Australia.

[drrockclub]

Close-up of the dropstone. Width is approximately 1.5 metres.

Cliff outcrop of the same dropstone.

Dolerite (igneous rock) in sandstone. This dropstone is indenting the sediment below and has sediment deposited on top draping over it, characteristic features of a dropstone.

Different exposure of a dolerite in the sandstone in planar view.

What are Dropstones?

Dropstone is an interesting geological feature found in the sedimentary rocks around the world. It literally is a stone that was dropped to the bottom of the water basin and is defined by being of a larger grain size than a surrounding sediment and therefore being deposited by a different process than the sediment around it. Dropstones have no sedimentological association with the surrounding sediment and typically range in size from pebbles to boulders and are found in sedimentary rocks that are formed by lakes, seas or oceans (large water basins).

There are five ways in which dropstones can form: dropped by glaciers, erupted out of the volcano (volcanic bomb), fallen meteorite, plant-based raft that sunk with rocks trapped within and brought in by strong turbidity currents flowing on the bottom of the ocean.

Here I will focus on and show you examples of the most common mechanism, the glacial source.

Imagine a place adjacent to a large water basin with rocks nearby which faces extremely cold weather conditions such as those during glacial period winters. As the glacier forms on the land and grinds its way over it, it will pick up rocks of various sizes along its way. Similarly, if river that flows into the ocean or a lake freezes completely over the winter period, it can engulf pebbles, cobbles and boulders with its ice which will become part of it. Or even winter months sea ice, it can also pick up any material that if lying along the coast.

Now, when winter comes to an end, and weather starts to warm up, the ice will start to melt, and frozen water body will start to move and dislodge from wherever it was attached to. These glaciers, frozen rivers or sea ice with embedded pieces of rocks will start to drift away from the land into the water basin as the surface currents drag the ice around.

As the ice continues to melt it will eventually start to drop those stones into the water basin. Stones will fall through the water column and hit the bottom of the sea or lake etc. This usually causes indentation within the sediment layers underneath the stone (see pictures) caused by the weight of the stone pressing on finer sediment it landed on. Sedimentation will continue on, burying the dropstones, and so we get a preservation of unusually large rock in unrelated sedimentological setting.

Why is this important?

Widespread emplacement of dropstones is commonly attributed to glacial periods, if geologist finds dropstones and other glacial period features such as the glendonites, it will allow a geologist to determine climatic conditions at the time of deposition for the geological formation of interest. It can also provide some insights as to where these rocks are coming from (provenance), if one can link dropped rocks back to the source.

Examples from south-eastern coast of New South Wales between Wollongong and Kiama, Australia.

[drrockclub]

Glendonite up close.

Close-up of the Permian glendonite fossil sticking out of the rock with much younger gastropod fossils on top of it.

and BIG glendonite deposit exposed on the rock platform in Australia.

Forgotten what glendonites are? Refresh your knowledge here with my previous post.

[oodlenoodleroodle]

Giant Mystery Crystals in Denmark Finally Explained

Some of the world's largest specimens of rare calcium carbonate crystals, known as glendonites , are found in Denmark. Researchers have long

[madcatwoman-enterprises]

THINOLITE Also known as Glendonite, this is a variety of Calcite. Colour: white to grey to pinkish-beige Found in:Australia A stone which is said to make one more effective when working with, and communicating with animals. REFERENCES & BIBLIOGRAPHY: Dana, E.S. (1884), A crystallographic study of the thinolite of Lake Lahonton: USGS Bull. 12. Palache, C., Berman, H., & Frondel, C. (1951), The System of Mineralogy of James Dwight Dana and Edward Salisbury Dana, Yale University 1837-1892, Volume II: Halides, Nitrates, Borates, Carbonates, Sulfates, Phosphates, Arsenates, Tungstates, Molybdates, Etc. John Wiley and Sons, Inc., New York, 7th edition, revised and enlarged: 160. Aquatic Geochemistry (1998): 4(3-4): 429-454. Photograph: taken from Mindat,public domain. More photographs can be found here: http://www.mindat.org/photoscroll.php?frm_id=pscroll&cform_is_valid=1&searchbox=Glendonite This is not an advertisement/endorsement of any seller or dealer above any other. Other companies selling this item are available. Text copyright: © madcatwoman 2014, www.madcatwoman.co.uk For detailed healing properties and photographs of many of the more common gemstones and minerals, please visit the Madcatwoman Enterprise Facebook page: http://www.facebook.com/pages/Madcatwoman-Enterprises/139677792795144?ref=hl&sk=photos_albums