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May 12, 2018 Weekly Geology Guest, Pumice

May 12, 2018
Image result for pumice images

 

Greetings from the Bluff Park Back Porch, way up yonder on Shades Mountain (1,109′) in Alabama:

We will now continue down the Industrial Mineral dusty trail and continue with Pumice

Pumice ( /ˈpʌmɪs/), called pumicite in its powdered or dust form, is a volcanic rock that consists of highly vesicular rough textured volcanic glass, which may or may not contain crystals. It is typically light colored. Scoria is another vesicular volcanic rock that differs from pumice in having larger vesicles, thicker vesicle walls and being dark colored and denser.[1][2]

USES
 
Pumice is widely used to make lightweight concrete or insulative low-density cinder blocks. When used as an additive for cement, a fine-grained version of pumice called pozzolan is mixed with lime to form a light-weight, smooth, plaster-like concrete. This form of concrete was used as far back as Roman times. Roman engineers used it to build the huge dome of the Pantheon and as construction material for many aqueducts.
It is also used as an abrasive, especially in polishes, pencil erasers, cosmetic exfoliants, and the production of stone-washed jeans. “Pumice stones” are often used in beauty salons during the pedicure process to remove dry and excess skin from the bottom of the foot as well as calluses. It was also used in ancient Greek and Roman times to remove excess hair.[8] Finely ground pumice is added to some toothpastes and heavy-duty hand cleaners (such as Lava soap) as a mild abrasive. Pumice is also used as a growing substrate for growing horticultural crops. Some brands of chinchilla dust bath are made of powdered pumice.
Owing to its high demand particularly for water filtration, chemical spill containment, cement manufacturing, horticulture and increasingly for the pet industry, the mining of pumice in environmentally sensitive areas has been under more scrutiny after such an operation was stopped in the U.S. state of Oregon, at Rock Mesa in the southern part of the Three Sisters Wilderness.[9]

Pumice is mixed with soil to provide good aeration for the plants. It is also used for hydroponics as a soilless growing medium.

>    Many specimens have a high enough porosity that they can float on water until they slowly become waterlogged.  as in Pumice rafts.

Related image
Specimen of highly porous pumice from Teide volcano on Tenerife, Canary Islands
User MPF on en.wikipediaOwn work
 

 

Kutkhiny Baty, a pumice rock formation outcrop located 4 km from the source of the Ozernaya River (Lake Kurile), near the southern tip of the Kamchatka Peninsula, Russia.

Image result for pumice images
Ahoy, Pumice afloat.

Sorry, No grande nor glorious nor Pretty pictures with this one, but one of those terribly important industrial minerals.  R

Our next industrial mineral challenge will be

Enjoy the adventure!
 
Thanks,
 

 

R
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