Today is another special day🙀 2 a ago during #hedgewatch on #LaGomera's highest point during #sunset the "thing with the ring" happened 🙀
The #gemstone on the #EngagmentRing is a #sapphire a variety of the #mineral #corundum which is aluminium oxide #Al2O3
⚒️🧪 geology
Congratulations #wavellite! Your soft translucent green and your radial shapes have us seeing starbursts. Farewell to #corundum, the ancient mineral that condenses from solar nebulae, will be back.
Corundum (as industrial sapphire) is not only scratch resistant, heat resistant, and acid proof; It can be a rod, tube, lens, or bearing. The only material that even comes close is diamond, but diamond is too brittle to make tubes.
You can even make tiny square vials called "cuvettes", which allow your sample to be heated to 1000s of degrees for spectral analysis.
(Most cuvettes are made of quartz, glass, or plastic, but for extreme tests, sapphire is sometimes used.)
I posted this last year, but here it is again:
This is a synthetic corundum rod from a hospital laboratory. These are called "industrial sapphire" despite the fact that they are pure Al2O3. Scratch resistant and non-reactive, a sapphire rod only a few cm long can be 2000C at one end and 20 C at the other, so you can test a wide temperature range with just one part.
Last week Clickspring posted a video showing how to use ruby (synthetic #corundum) bearings in precision instruments.
Corundum bearings are hard (mohs hardness 9) and shaped and polished to be low-friction.
GeologistsCat
Claudia Zahn
Mineral Cup
dlw
brds
David Michael Self
Bill Minarik
John Faithfull 🌍🇪🇺🏴🧡✊🏻✊🏿