Lapis lazuli was a fine stone used a lot during antiquity by Egyptians and archeologists have found a lot of lapis lazuli intaglio jewelry from ancient civilizations.īeing quite soft, Lapis lazuli can be engraved easily with this CNC process as you can see hereafter. On the left, the design is made with 30 passes while on the right, the deep engraving of the same design is made by hand with specific tools and this intaglio allows the making of wax seals. Here is another comparison of a design engraved on carnelian stone by CNC means and traditional carving made by hand. It is necessary to remark that while this seems a lot, this process is still faster and much cheaper than a traditional intaglio hand carved. The ant engraving on this carnelian stone required 25 engraving passes to give the result shown in the picture. While the CNC engraving on carnelian stones gives a result, we can visualize that this stone is harder than onyx stone and require more engraving passes to give good results. On the contrary, the engraving we are able to make with this CNC engraving is flatter and is not usable to make a wax seal, still it is visible to the naked eye. Traditional intaglio is made with tools carving the stone tenth of a millimeter deep so it was possible to make a wax seal with such a stone. Archeologists have found a lot of ancient intaglio rings set with carved intaglios representing animals, divinities or objects of everyday life dating back from the romans.Īs ants were one of the animals represented on roman intaglio rings, we have used this example to make a comparison of a traditional antique carnelian intaglio with this CNC carving method. You can note that less engraving passes affect the visibility of the engraving Carnelian IntaglioĬarnelian stones were used a lot during antiquity to make intaglio rings or intaglio jewelry for seal purpose. Here is another onyx CNC carving of initials with only 5 passes. Here, the engraving is deep enough to be clearly visible and you can feel it with your finger Here is the final result after 15 passes. Once the dust is cleaned, it can be hard to see the engraving from a distance, this is the reason why we repeat the carving program several times. View of the first pass of CNC engraving on this onyx stoneįor each pass of the diamond tip, few microns of material are scratched from the surface. The engraving is large, made of thin lines and the engraving is repeated 15 times to allow the diamond tip to engrave deep enough so we can feel the engraving with our finger tip. Onyx intaglioįor this test, we made a logo engraving with initials at the center. Here you will find the complete list of gemstone with their indicated hardness. I have tested this engraving method on a small panel of fine stones: The advantage of the CNC machine is that it is very precise, and we can repeat the number of passes without losing the details of the engraving.Īs you will discover, while the diamond tip is the best option to engrave gemstones, one engraving pass is just not enough to get a proper engraving result. View of the AM30 CNC Engraving Machine linked to the computer that commands the moves of the diamond tipĪs a reminder, diamond's hardness on Moh's scale is 10 and the majority of the stones engraved by this method described in this article have a Moh's scale hardness around 7. The diamond tip is a standard one as this is the best option to engrave any surface, so we use it to engrave our gemstone. In our case, we use an AM30 jewelry engraving machine usually used for engraving silver and gold jewelry. To engrave our fine stones, we use a diamond tip driven by a CNC machine link to a computer using a specific software. Quick view of intaglio made with the CNC engraving machine on fine stones to be used in jewelry The engraving tools We will detail the carving method used, the pros and the cons and suggestion to improve it. Many people interested in this form of art are not wealthy enough to affort such prices, and while asking us for a solution we had the idea to test a CNC carving method on gemstone, that we are going to present in this article. Some jewelry carvers specialized in reproducing such ancient intaglio gemstone, and the cost of such artwork usually ranges from $300 USD to $800 USD. While intaglio in jewelry is not fashion nowadays, there are still people fascinated by this form of art and looking for ancient intaglio rings made of carnelian or onyx stone. Such form of art dates back from antiquity, the most ancient intaglio ring discovered by archeologists is estimated to be 3000 years old. Intaglio jewelry is a very specific form of artwork consisting in carving a fine stone to represent a shape, a face, a life event or a religious scene.
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