Breaking The Vessel
The process of creating a cracked glass sphere has some really great symbolism. You heat the vessel to a high temperature; expanding it. Then you submerge the glass in a cold temperature. The outer layer of glass shrinks rapidly. This creates fractures in the glass without shattering it. it's an amazing process amazing and the results can be beautiful.
I've made my own little tutorial using a larger sphere but here are the original steps that I followed from WikiHow with marbles instead (same process): https://www.wikihow.com/Make-Cracked-Marbles
The Glass Sphere / Crystal Ball
I purchased a K9 crystal ball. You can get these on amazon and many other online stores by searching "K9 crystal ball" (go figure). They come in many different sizes. The images can be deceiving so be sure you know what size you're getting (the big ones are heavy!).
This is the one I purchased on amazon (if the link is still active): https://www.amazon.com/gp/product/B07BXV7YGH/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1. It's a size 80mm / 3.15". You can get an idea of the size relative to the photos I took for the tutorial.
WARNING: When you purchase the ball, be very cautious about having it exposed to direct sunlight. It is a magnifying glass, a really good one, of the kind that has destroyed whole civilizations of ants. I've torched a few things on purpose and some things on accident. It melted the cupholder in our car once and I realize it could have caught the car on fire if I hadn't gone to get something out of there and noticed a strange burning smell. The other day it started burning my hand when I carried one outside unwittingly. It's no joke! Be careful!
Step 1:
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Step 2
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Step 3
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Step 4
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Step 5
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Step 6
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This is a fun little video just messing around with the broken sphere (this is a larger one than what is in the photos above) using a headlamp in a dark space. The refractions are mesmerizing, so go experiment ya own-self!