And on even rarer occasion a carved sapphire seal comes to light, but these are quite rare and were usually reserved for royalty and/or papal seals. On rare occasion one may come across an intaglio seal carved into mother of pearl, but they are uncommon because mother of pearl is rather fragile. At Seal & Scribe, we rather like the slight feathering on a gem stone seal because it serves as a reminder of the painstaking skills required to carve on to a gem stone, and is another aspect of the provenance of the stone. While one can get a crisp line on gem stone seals, there is often slight feathering on some lines, which no doubt appear because if one were to polish certain areas on a gem stone seal the actual hand-engraved lines would be diminished. The use of certain semi-precious and even precious gem stones is less common than hard stones - no doubt because of their cost - and the most common gem stones used for intaglio seals are of the quartz family: amethyst, citrine, rock crystal, etc.
One could get a clear, crisp etching image and text, just as with using metal seals, however the hard stone seal had an added bonus of the coloring of a beautiful stone to enhance the seal itself.
Stones such as: carnelian, bloodstone, chalcedony, and agates were most common during the 1700s to 1800s. Hard stone seals tend to use certain stones that are hard enough to provide a good, smooth surface for detailed etching. Such seals were primarily used for seals that required a very high level of detail, such as family crests and coat of arms, royal ciphers, monograms, etc. Engraving into metal would give a seal a very crisp level of detail because etching into metal provides a certain quality of stability and hardness to etch into, and even the smallest of engraving tools can leave crisp, clean lines in the image and text on an all-metal seal. One can find all-metal seals in gold, silver, brass and copper, as well as 'pot' metal which is a mixture of non-precious metals. Metal seals come in a variety of metals that were available during Georgian and Victorian times. Each seal medium has it's own beauty and merits, so let's explore each one on it's own: Intaglio seals come in four basic mediums: all metal, hard stones, gem stones, and glass.