Black beads can be incredibly common or incredibly uncommon, depending on the region you are in. South Asian contexts tend to have more black beads than most places, and Victorian England had a lot of black beads. But they’re virtually nonexistent in certain areas of Southeast Asia, Africa, and the Americas. Why? Because in many places, black is the color of death, and not a color to be worn while living.
That being said, black beads aren’t nearly as uncommon as purple beads, despite their common associations with death. This actually isn’t all that surprising, since the association with death could mean they adorned the dead in many regions and would still be in demand in the bead market.
Historically, black beads were be made of jet, glass, or onyx. As discussed in an earlier post, many glass beads appear black, but turn out to be dark blue, green, purple, or even hot pink when you shine a light through them. But there are a sizable number of black glass beads that are in fact black, and they can be either translucent or opaque.
This brings up an important point about recording both what color a bead appears to be without special lighting and what color it is with the LED light through it. Just because it looks hot pink shining an LED light through doesn’t mean anyone in the past was able to find a light strong enough to get the same effect – to them, it was as black a bead as any that are black when back-lit by LED. If you’re interested in how that person perceived the bead, then it’s worth thinking about what sorts of lighting were available to them.
Black glass is made by adding larger amounts of manganese, cobalt, and/or iron to the glass, which is why many appear actually green, purple, or blue when shining a light through. When mixed together, they create a solid black color. As I said above, though, you can get a bead that appears black in all historically available lighting simply by making a very dark green, blue, or purple bead. This was a lot more cost effective or efficient, because you didn’t need to add multiple rare or valuable ingredients to your glass to get the desired color.
Jet is a black material commonly used for beads in Europe. It comes from highly pressurized, decayed wood, and is a precursor to coal. The most commonly cited source is at Whitby, England and is roughly 182 million years old. Jet is therefore an incredibly common material in the British Isles and much of Europe from the Neolithic through the Roman period as a protective amulet. Its popularity dropped significantly until Victorian times, when it became immensely popular for the process of mourning. Queen Victoria often wore jet jewelry to mourn her husband, Prince Albert, in the forty years after his death.
Jet is considered a semi-precious stone, and often looks very much like glass or onyx. To distinguish between them, simply hold a glass bead of similar size in your hand (any color works). The warmer bead is jet, since jet has a lower thermal conductivity. If you can’t tell which is warmer, the lighter bead is also jet, since glass generally has a higher specific gravity.
Onyx is probably the most common stone used to make black beads. It’s part of the chalcedony family and is also silica-based. The only difference between onyx and agate is the bands: agate has curved bands while Onyx has parallel ones. This means that onyx can be any in a range of colors, though we mostly associate it with black. Black onyx does occur naturally, but it’s fairly rare. Since ancient times, artificial methods have been used to color the stones black, such as boiling the stone in sugar and then treating it with sulfuric or hydrochloric acid to carbonize the sugars soaked into the top layer of stone.
Onyx is a very hard stone, and therefore difficult to carve. Many objects sold as carved onyx today are therefore most likely a carbonate material and not actually onyx. There are even glass beads dating to ancient times made to look like onyx beads, in which black glass and white stripes are combined and folded into a bead. These are often known as zone beads, and many of them appear very similar to specific types of stones.
All in all, black beads aren’t very rare in the archaeological record, but they tend to be made of materials that are harder to procure. That coupled with their common association with death often makes black beads generally uncommon in many regions.