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PRODUCTS BY WEIGHT
BOX SETS
PLASTIC DISPLAY PRODUCTS
PRODUCTS BY WEIGHT
BOX SETS
PLASTIC DISPLAY PRODUCTS
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Obsidian is a naturally occurring volcanic glass derived from a rapidly cooled high silica lava. Often associated with the margins of Rhyolitic lava flows. It has little or no discernable crystalline structure. Specimens are supplied in a polythene bag in lots of 1 kg with a label.
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Obsidian is a natural volcanic glass. An extrusive igneous rock. It is produced when silica rich lava extruded from a volcano rapidly cools minimising crystal growth. Obsidian is commonly found within the margins of rhyolitic lava flows known as obsidian flows. The high silica content (70 -75%) produces a highly viscous lava with some degree of polymerization. The inhibition of atomic diffusion through this highly viscous and polymerized lava explains the lack of crystal growth. It is classed as metastable as over time it will crystalise. Non has been found over Cretaceous in age. Obsidian is hard and brittle with a concoidal fracture it therefore breaks with very sharp edges, which were used in the past in cutting and piercing tools. It has been used experimentally as scalpel blades.
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Snowflake obsidian is quite striking in appearance. It is characterised by the inclusion of radially clustered crystals of cristobalite, which when viewed at a glance, appear like snowflakes on the surface of the rock. These crystal clusters are set in an otherwise black vitreous matrix of obsidian, which is an naturally occurring volcanic glass, even exhibiting a conchoidal fracture. Cristobalite is a high temperature polymorph of silica, it can form as a result of the devitrification of the obsidian. These specimens come from Java, Indonesia and are supplied in card trays, sizes which are optional, each tray also has a small data label supplied.
We also supply Snowflake Obsidian thin sections for microscope study which are available to buy HERE.
This Mahogany obsidian is sourced in the United States of America. Impurities of magnesium and iron give this variety a red or brown appearance hence the name ‘mahogany obsidian’ or oak obsidian. Specimens are supplied in a polythene bag in lots of 1 kg with a label.
Out of stock
Obsidian is an extrusive igneous rock, these specimens exhibit a typical black colouration with conchoidal fractures, they come from South East Mexico and are excellent for educational use and collectors due to the quality. This igneous rock forms when magma extrudes onto the earths surface, chemically it is silica rich and impurities give the black colouration. It’s fine crystalline texture and fracture makes obsidian appear glassy and it breaks as such. The pieces are available in various sizes and come supplied in a card tray with an information label.
We also supply Obsidian thin sections for microscope study which are available to buy HERE.
Rhyolite Felsite, a highly felsitic composed variation of Rhyolite, found in Scotland. Specimens are supplied in a polythene bag in lots of 1 kg with a label.
Mahogany obsidian sourced from the United States of America. Impurities of magnesium and iron give this variety a red or brown appearance hence the name ‘mahogany obsidian’ or oak obsidian. Each Sample is supplied in a labelled card tray.
Out of stock
Stunning peridotite thin section exhibiting the bright and beautiful colours of olivine and pyroxene punctuated by relatively abundant plagioclase. Peridotite is a dense, coarse grained, ultramafic igneous rock consisting largely of olivine and pyroxene.
7 in stock
Micro Granite is a variation of the granite group of rocks, composed of the minerals quartz, feldspar and mica. These particular samples were collected from Threlkeld quarry, Cumbria, UK. Specimens are supplied in a polythene bag in lots of 1 kg with a label.
Big feldspar gabbro thin section exhibiting exactly what its name describes, feldspar crystals much larger than those present in the ordinary gabbro which we supply. Characteristic twinning in the plagioclase and the bright colours of the pyroxene make for an attractive thin section, perfect for educational use.
We provide a full range of igneous, sedimentary, metamorphic and mineral thin sections. Click here to view them. Should you require a microscope, they can be found here.
7 in stock
Rhyolite thin section slide exhibiting the fine grained nature of this felsic igneous rock. The thin section shows a silica rich mineral assemblage of fine grained quartz and plagioclase. Accessory minerals present include biotite mica and hornblende. This material was collected from Cumbria, UK.
7 in stock
Pumice thin section slide exhibiting the highly vesicular nature of this extrusive igneous rock. Pumice lavas tend to be silicic or felsic which are highly viscous thus do not allow the gas bubbles to escape efficiently.This material was collected from the Lipari islands of Italy.
9 in stock
Banded rhyolite from Glen Coe, Scotland showing laminar flow banding which was produced by the viscous lava which formed the rock, available in various sizes, these specimens are suitable for educational use to display flow banding. Supplied in a card tray with an information label.
65 in stock
Metagabbro specimens from Lom, Central Norway. Also known as scapolite-hornblende due to the absence of feldspar in the rock are available in 3 optional sizes and come supplied in a card tray with a data label.
40 in stock
Adamellite granite also known as shap granite from Cumbria, famous for its large pink feldspar crystals his granite is well known. The samples come from the Shap Quarry, Shap Fell, Cumbria and are supplied in a polythene bag in lots of 1 kg with a label.
Rhyolite specimens found in Cumbria. Rhyolite is a felsic (silica rich) rock, often formed in highly explosive volcanoes. Specimens are supplied in a polythene bag in lots of 1 kg with a label.
Microgranite thin section slide exhibiting the medium grained nature of this intrusive igneous rock. The crystals in microgranite are smaller than those of normal granite indicating that it cooled at a quicker rate.
We provide a full range of igneous, sedimentary, metamorphic and mineral thin sections. Click here to view them. Should you require a microscope, they can be found here.
7 in stock
Shap granite igneous rock specimens from Shap Fell, Cumbria, UK which exhibit typical coarse grained crystalline textures expected of intrusive felsic rocks, being composed of quartz, plagioclase and orthoclase feldspar and biotite mica. This popular granite is very sought after for a variety of applications and has a colourful appearance. It is believed to have formed during the early Devonian period as a plutonic intrusion in the area and is quarried extensively. Samples are ideal for collectors of all levels and ages as well as all educational levels as the minerals can be easily described with the origin and processes being suitable to teach higher level students. Samples are available in three sizes and come supplied in a card tray with an information label.
We also supply Shap Granite thin sections for microscope study which are available to buy HERE.
Specimens of Puddingstone, collected from Hertfordshire, UK. Puddingstone is a variation of conglomerate, which is term used to describe a coarse grained sedimentary rock, featuring large, well rounded clasts in a finer grained matrix. It dates back to the Paleocene to Eocene period around 56 millions years ago. This particular rock is composed almost entirely of silica and has no porosity, likely contributing to its notorious hardness. This rare rock is only found in quantity at one locality in Hertfordshire. As such, it is becoming exceedingly difficult to obtain. This rock is available in multiple sizes and each piece comes supplied in a white card tray with information label.
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