What are the different types of intaglio seals?

Intaglio seals come in four basic mediums: all metal, hard stones, gem stones, and glass. Each seal medium has it's own beauty and merits, so let's explore each one on it's own:

 1. Metal seals

Metal seals come in a variety of metals that were available during Georgian and Victorian times. 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. 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. 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.

2. Hard Stone seals 

Hard stone seals tend to use certain stones that are hard enough to provide a good, smooth surface for detailed etching. Stones such as: carnelian, bloodstone, chalcedony, and agates were most common during the 1700s to 1800s. 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.

3. Gem Stone seals

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. 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. 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. 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. 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.

4. Glass seals

Last but by no means least, we have glass seals, which were produced often not as one-of-a-kinds (like a family crest might be), but rather for the masses and as such, a scribe might purchase a set of glass seals so that he could offer his customers the use of a seal to secure their correspondence, just like the well-heeled gentry of the time period. These glass seals were developed and perfected by James Tassie (1735–1799), a Scottish gem engraver who eventually began perfecting the modeling of small gem-like intaglio seals from paste glass. Many Tassie seals have cheeky, whimsical mottoes that go with the image on the seal, and there are also Tassie seals that are laden with beautiful imagery and deeply sentimental mottoes. Lastly, some glass seals carry a rebus -  a combination of pictures and words/letters that, when put together, form a message. Victorians loved the rebus as a message device because they were keen on 'hidden meanings' as being overt when conveying one's feelings was seen to be inappropriate and discretion was of the utmost importance.