A pair of jet black amethyst glass antique apothecary jars from Europe circa 1830. The mushroom stoppers have a striking starburst design; each curved ray has been skillfully and painstakingly cut by hand.
Opaque glass was a desirable quality in pharmacy jars because it kept out sunlight which would accelerate the oxidation and breakdown of chemical compounds. Dark tints were made by adding various salts, chromium oxide (green) cobalt (blue) and gold or selenium (red). Amber was by far the most common and progressively less so green, blue, red, purple and black. Most dark glass when held up to the light will reveal its base colour.
These jars are pitch black from the addition of manganese, cobalt and iron salts, and this degree of opacity was not an easy appearance to achieve in the early 19th century. Relatively few were made, making them rare and much sought after. The pontils are smooth and polished.
Kalium Iodatum was used in mercurial, syphilitic, and scrofulous affections. Also in secondary syphilis, especially after abuse of Mercury or combined with scrofula, buboes and chancres. Kalico Silver Nitrate may have been used a dye for printing on silk and animal materials.
[Apothecarial demands aside, clear glass was the order of the day in the late 19th century. The iron in sand gave most early clear glass a light green to an amber tint. As an alternative to the expensive use of lead to produce clear lead crystal, factories using iron-bearing sands started to add manganese to their batches as a decolourant from around 1880. This produced a clearer glass, but which turned a light purple or amethyst color when exposed to ultraviolet and sunlight].