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66 CTS A GRADE RAINBOW OBSIDIUM SLAB [F5750]

SKU
Dimensions (mm)
44.000 x 25.000 x 7.000mm
Weight (cts)
66.000
Type
Rough
Colours

QUALITY ROUGH

A GRADE OBSIDIUM SLAB

This is a piece we cut off a rough specimen at app 45 degree angle to expose the amazing patterns.Great cutting experience.We have taken the photo with the rough wet.

General
CategoryVolcanic glass
Formula (repeating unit)70–75% SiO2, plus MgO, Fe3O4
Identification
ColorDeep black or blackish green
FractureConchoidal
Mohs scale hardness5–6[1]
LusterVitreous
Specific gravity~2.4[2]
Optical propertiesTranslucent
References[3]

Obsidian is a naturally occurring volcanic glass formed as an extrusive igneous rock.

It is produced when felsic lava extruded from a volcano cools rapidly with minimum crystal growth. Obsidian is commonly found within the margins of rhyolitic lava flows known as obsidian flows, where the chemical composition (high silica content) induces a high viscosity and polymerization degree of the lava. The inhibition of atomic diffusion through this highly viscous and polymerized lava explains the lack of crystal growth. Obsidian is hard and brittle; it therefore fractures with very sharp edges, which were used in the past in cutting and piercing tools, and has been used experimentally as surgical scalpel blades. It may contain patterns of gas bubbles remaining from the lava flow, aligned along layers created as the molten rock was flowing before being cooled. These bubbles can produce interesting effects such as a golden sheen (sheen obsidian). An iridescent, rainbow-like sheen (rainbow obsidian) is caused by inclusions of magnetite nanoparticles

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Rest of the world
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Registered Shipping $9.00 / 7 days $16.00 / 21 days
Australia
Registered Shipping is discounted to $9.00 on orders with 2 or more items
Rest of the world
Registered Shipping is discounted to $16.00 on orders with 2 or more items

mineralgemworld
mineralgemworld
MEMBER OF THE [ICA]  INTERNATIONAL COLOURED STONE ASSOCIATION AND PRESIDENT OF THE OPAL ASSOCIATION. We have a retail shop/museum at the Gold Coast Opal and Gem Centre 25 surfers av mermaid waters Qld Australia .4218 open mon to sat 10 to 5
Surfers Paradise, Australia
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8.00%
Coupon code GEMSONSALE
Valid Until
21st Apr 2024

Audit

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Shipping Details

Shipping:
$16.00 21 days via Registered Shipping
Ships from:
Australia

Payment Options

  • paypal
  • stripe
This seller adds 10.00% tax to transactions in Australia.

Overview

Listing Type : Standard
Product ID : 492578
Starts : 27th March 2024 08:55 pm PDT
* All prices are in USD