Non-crystaline Minerals

Obsidian

Sometimes the magna expelled from a volcano cools so quickly that crystals are not able to form. If the magna is rich in silica it forms a type of glass called obsidian.

Chemically, obsidian is very similar to the igneous rocks, granite and rhyolite. If the magna cools slowly, deep within the Earth, it forms large crystals of granite. If it cools more quickly, near or on the Earth's surface, it forms smaller crystals of rhyolite.

 

Tektites

Tektites are lumps of glass, usually small, which are associated with meteorite impacts. They may be shaped like tears, rods, disks, buttons or dumb-bells. They may be black, brown or green.

Tektites may be either the remains of meteorites or they may be formed when meteorites hit the Earth. The collision causes molten rock to be ejected into the air. The molten rock cools quickly to form small glass beads.

Tektite

 


 

Non-crystaline specimens now available (at eBay):

Click on an item to view details and, if you wish, bid.

Mahogany Obsidian Polished Ball/Sphere 35mm Diameter, 55g

AU $18.34
End Date: Wednesday Oct-2-2019 8:19:17 EST
Buy It Now for only: AU $18.34
Buy It Now | Add to watch list

>

TEKTITE - Indochina Tektite nodule - natural - 5.5x4.4x2.1cm 72g NICE!!

AU $18.90
End Date: Wednesday Oct-16-2019 17:32:01 EST
Buy It Now for only: AU $18.90
Buy It Now | Add to watch list

>

Polished TEKTITE Indochina A++ 26g Large Tumblestone Tumble Freeform NICE

AU $10.00
End Date: Wednesday Oct-16-2019 17:17:19 EST
Buy It Now for only: AU $10.00
Buy It Now | Add to watch list

>

69g WHITE CHRISTOBALITE INCLUDED BLACK OBSIDIAN polished CRYSTAL STANDING POINT

AU $14.99
End Date: Friday Oct-11-2019 17:41:07 EST
Buy It Now for only: AU $14.99
Buy It Now | Add to watch list

>

TEKTITE - Indochina Tektite nodule - natural - 5.8x4.1x1.6cm 63g NICE!!

AU $14.90
End Date: Tuesday Oct-22-2019 19:30:32 EST
Buy It Now for only: AU $14.90
Buy It Now | Add to watch list

>

TEKTITE - Indochina Tektite nodule - natural - 4.6x4.1x2cm 57gNICE!!

AU $14.90
End Date: Tuesday Oct-22-2019 19:27:57 EST
Buy It Now for only: AU $14.90
Buy It Now | Add to watch list

>

Polished TEKTITE Indochina A++ 10g Tumblestone Tumble Freeform, Unique! NICE

AU $6.20
End Date: Friday Oct-18-2019 19:19:13 EST
Buy It Now for only: AU $6.20
Buy It Now | Add to watch list

>



FAQs | About Us | Contact

Copyright © Peter Thorogood

Web design by Peter Thorogood