I know about casting stones in wax using diamonds and corundrum is there any chance one could cast while embedding Alexandrite?
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Who would cast a stone in wax, then use the lost wax casting process to form the metal structure around it? Once the wax has been burned out of the mold, what would keep the stone in place?
The temperatures needed to flow metal into a casting typically requires the flask to be pre-heated to ensure no moisture and good flow into the cast when pouring the metal.
In the 40+ years of metalsmithing, I have never subjected a facetted stone to those temperatures. Sure, heat treatments use similar methods (lower temperatures)… but even those have risk of damage or negative effects on the stone.
Seems a scary venture…
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Nancy Klotz nk@nkjewelart.com 2:15 PM (1 minute ago)
to Troy
I cast pieces with the stone embedded all the time to great success. I am doing one of a kind pieces. I am not making a mold from the carved wax. I have used diamonds , sapphires and rubies with no ill-effect. I do not know if you are familiar with the jeweler Polly Wales but she also has been doing this for many years If you know what you are doing it is quite nice for unique designs
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Nancy,
Thank you! I would have never considered this technique. The approach is intriguing and the methods are definitely not traditional… 
Very curious now!
To get back on subject (sorry for my panicked response), Alexandrite is sensitive to temperature. Several literatures state it is sensitive to extreme temperature change, but I haven’t found to what level or to what extent the sensitivity is. My first reference is Bruce Knuth’s Jeweler’s Resource; ISBN 0-9643550-3-5. It has been my “paper brain” for several decades, now.
IGS info states similar caution.
I have never done repairs on articles with Alexandrite stones in-situ. I always remove them from the setting or shield them from the hot-work.
Cheers!
Troy
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Thank you so much Troy! This will be very helpful! Nancy
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Don’t risk damaging any ALEXANDRITE by hot casting. Heat a piece of scrap alexandrite or chrysoberyl in last wax casting and, after it has completely cooled, check the appearance of the test piece. Often an unseen defect or crystal structure can cause unexpected results.
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I have to agree with Troy and Frederick on this topic. I would never risk subjecting a stone to sudden and intense heat. Even doing repair work, it’s best to remove the stones and/or use a heat shield and heat sink. Thermal shock runs the risk of cracking a stone, even if it seems solid and free of cracks. Even conrundum stones can crack. Heat treatment is done with gradual temperature rise and gradual cooling to avoid thermal shock. This is not the case when exposing a stone to molten metal suddenly. Flask burnout temperatures are much lower.
Thank you all for this info. I might experiment and report back