Hello! I am new on this forum, and I thought that it would be useful to ask a hard question on. I have a faceted 6 ct proustite gemstone that I would like to wear as a pendant. The proustite is a diamond cut, and 9cm x 9cm. I plan on having a goldsmith make the setting for the proustite, so the proustite will be encased and surrounded by 18 k gold. The gold setting will cover the back and sides of the proustite, but the front will be displayed and exposed as the centrepiece of the pendant.
The problem is that a proustite has a hardness of only 2.0 - 2.5. Also, when exposed to light (such as sunlight), a chemical reaction takes place that will slowly cover the beautiful red gemstone with silver. This process is irreversible as far as I know, and will ruin the gemstone.
To prevent scratches and the silver chemical reaction, I propose covering the gemstone with a thin layer of borosilicate glass. Borosilicate glass has approximately a hardness of 7, and borosilicate glass can either be made, or is, almost 99% UV light resistant. Thus, this would protect the colour of the gemstone, and scratching.
I envision this, however I’m not sure how this can be done. Does anyone know who (or if anyone can) make borosilicate glass custom made to fit the shape of the exposed gemstone? Also, how would the glass be fitted into the gold framing surrounding the gemstone? Can anyone tell me if borosilicate glass is, or can be made to be 99% UV light resistant, or close to this?
I presume your proustite is a 9 mm X 9 mm square cut stone. Borosilicate glass makes up the beaker part in plunger coffee makers so the base of one of these could provide some flat pieces. I am not sure that such glass prevents transmission of all sunlight Ultra Violet. In any case, placing glass on top of a cut gemstone may introduce internal reflections thus demeaning your proustite.
Not sure I’d use glass, a low cut cabochon of quartz, topaz, goshenite or any colourless, clear stone would be better than glass.
I’d also get a full evaluation of the proustite value too, its a bitch to prove once its sandwiched between gold and glass
Yes, PL01, maybe using a low cut cabochon clear stone is better. However, can you tell me a gemstone that would be clear like borosilicate glass and about 99% UV light resistant? If you come up with any more ideas, feel free to post them. Thank you!
Quartz is transparent to ultraviolet light. I’m not sure about other colorless minerals. A transparent glue such as epoxy with an UV absorber would avoid UV damage and minimise internal reflection but would diminish the value of your stone. Perhaps your stone is best worn at night under artificial light ie no sunlight.
Thank you, IvanIvarsD72471. I would like to wear my gemstone during the daytime, even in bright sunlight (I’m in a geographic location with much sunlight), and I am mostly outside to places during the daytime. I’ve been thinking about using a UV resistant coating on top of the borosilicate glass/quartz. It would be most preferable, if the UV light resistant properties can be an embedded part of the material.
Thank you for your responses, these are good ideas. If anyone has any other ideas, please feel free to post. I will read them!
I recently have been thinking… and using some thin glass / other transparent gemstone (thus giving a ‘glass frame’ to the gemstone, similar to picture framing glass to a photo or a painting) and treating the glass with the same shield material that are used on UV 400 resistant non-tinted sunglasses. But there may also be a picture frame glass cutter that can make the lens; there may be a glass material that already exists for this type of UV resistance that protects paintings and photography in museums. I will do more research, and if anyone has any other ideas, please post them. I will post what I find out! Thank you!