My recent post on dichroic glass was about man-made fused glass. Did you know there are also such things as natural fused glass?

1.Fulgurite/Petrified Lightning Glass

Fulgurites occur when lightning strikes sand. They are sometimes known as petrified lightning. Tube- like structures form when the high heat (1800 -2500 degrees C) of the lightning strike melts and fuses quartz sand to form silica glass. Their colour will depend on the sand composition.

They could resemble carrots or tree roots below ground and vary in size from a few centimeters to several metres long. The shapes are dictated by the path taken by the lightning. They are often hollow because the intense heat literally vaporises the material inside. The interior is glassy because of the rapid cooling after the strike. You can see some pictures of fulgurites including a long one being excavated here. Less common than sand fulgurites are rock fulgurites which are more like coatings or crusts of glass on rocks.

Fulgurites are relatively rare so I was pleasantly surprised to stumble upon Science Mall (no affiliation) which actually sells wire wrapped sand fulgurites as shown in the picture. According to them, when fulgurites are gently tapped, a wind chime sound can be heard. Each sound is unique to the fulgurite. If you are scientifically inclined or simply just love unusual jewelry, I suggest you take a look at their site.

Jewelry artisan, Carol Stanyon of Gentle Swan Studio, wrote about some special pendants she designed for a client whose yard was hit by lightning on the day her father died. This lady found green to black round glass beads, clusters and some of the classic fulgurite tubes. You can see Carol's lovely and meaningful creations here.

2. Volcanic Glass

Volcanic glass really needs no introduction as many of you know it as the gemstone, obsidian. It is formed when lava rich in silicate material is extruded from a volcano. The rapid cooling does not permit crystal growth. As it lacks a crystalline structure, it can be made into thin sharp cutting and pointed tools. This property was exploited by ancient people to make arrowheads and knives. Even today, it is used in cardiac surgery because its sharpness beats that of steel surgical scalpels.

For us jewelry designers, black obsidian makes a lovely alternative to hemalyke/hematite. This cute snowflake obsidian pig shows spherulites, the crystalline fibrous material that makes this gemstone variation so pretty. Pele's tears and Apache tears are other forms of obsidian.

What are fulgurites and where can they be found? 

Original Post by THE BEADING GEM
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