Hands-On Archaeology: How to Use Lac, the Amazing, Mystical Mastic

Preservation Archaeology Blog

We hope you enjoy this post from our most prolific blogger, Allen Denoyer. Thanks for all the great posts, Allen!

Allen Denoyer, Ancient Technologies Expert

(August 29, 2025)—Earlier this year, I shared information about how to ethically harvest lac. Prior to that, conservator Marilen Pool wrote about lac use in the ancient Southwest. In this post, I want to show you some of the projects I’ve been doing involving lac. People did almost all of these things in the ancient and more recent past, and lac is still being used today.

Ground lac. I’ll talk more about this below.
Ground lac. I’ll talk more about this below.
Lac used to fasten a handle to a gourd.
Lac used to fasten a handle to a gourd.

Let’s start with how I’m learning to process lac for use.

This is a little steamer pot usually used to quickly boil water. I put a natural lac stick in it, boil with water, and watch the lac globs come off the sticks quite easily. I do this so the lac comes off cleaner, without lumps of bark and the like. I use the remaining water, which is now dyed, in my shell etching and dyeing process.
This is a little steamer pot usually used to quickly boil water. I put a natural lac stick in it, boil with water, and watch the lac globs come off the sticks quite easily. I do this so the lac comes off cleaner, without lumps of bark and the like. I use the remaining water, which is now dyed, in my shell etching and dyeing process.
This is what I mean by bark, etc. This is Rosary babybonnet lac on stems (stick lac). This is what I boil in water.
This is what I mean by bark, etc. This is Rosary babybonnet lac on stems (stick lac). This is what I boil in water.
Lac after boiling the stick lac and then scraping it from the sticks.
Lac after boiling the stick lac and then scraping it from the sticks.
Next step: Here I am heating the lac in a disposable pie tin over a solo stove. Be careful, here—it’s easy to catch the lac on fire. And this step in smoky—best done outdoors.
Next step: Here I am heating the lac in a disposable pie tin over a solo stove. Be careful, here—it’s easy to catch the lac on fire. And this step in smoky—best done outdoors.
Once the lac is melting down, I begin to affix layers of it onto a stick/wand I can use later as a handy applicator. I dip my gloves in water continually so the lac doesn’t stick too much.
Once the lac is melting down, I begin to affix layers of it onto a stick/wand I can use later as a handy applicator. I dip my gloves in water continually so the lac doesn’t stick too much.
I’ve been told that the Tohono O’odham used an applicator stick like this for mending pottery and coating game balls, among other tasks.
I’ve been told that the Tohono O’odham used an applicator stick like this for mending pottery and coating game balls, among other tasks.
Here’s another use: I’m inserting a biface into a lac-filled slot on a replica Tohono O’odham sword.
Here’s another use: I’m inserting a biface into a lac-filled slot on a replica Tohono O’odham sword.
Here’s a knife hafted with lac.
Here’s a knife hafted with lac.
A projectile point hafted with lac.
A projectile point hafted with lac.
Above I mentioned stone balls. These were used in various sizes in various traditional games. Here’s a finished ball with a stone core, so it has heft. The lac covering this ball is from T. fulgens from the Rosary babybonnet plant.
Above I mentioned stone balls. These were used in various sizes in various traditional games. Here’s a finished ball with a stone core, so it has heft. The lac covering this ball is from T. fulgens from the Rosary babybonnet plant.
The previous stone ball in production.
The previous stone ball in production.
The previous stone ball in production.
The previous stone ball in production.
Two ironwood-core balls and one uncoated stone ball. I’ve since learned that wood-core balls were more like softball-sized, and stone balls were much smaller.
Two ironwood-core balls and one uncoated stone ball. I’ve since learned that wood-core balls were more like softball-sized, and stone balls were much smaller.
For some projects, I prefer to grind the lac almost to sandy consistency. That “melts” better in alcohol for use as a resist in my shell-etching process, which is loosely based on examples of etched shell found in sites of the Hohokam archaeological tradition.
For some projects, I prefer to grind the lac almost to sandy consistency. That “melts” better in alcohol for use as a resist in my shell-etching process, which is loosely based on examples of etched shell found in sites of the Hohokam archaeological tradition.
I use a mortar and pestle to grind the lac.
I use a mortar and pestle to grind the lac.
Yes, I know this next step is not authentic, but this is what I do for now! To “melt” my lac, I mostly use plain ol’ rubbing alcohol, and sometimes lacquer thinner.
Yes, I know this next step is not authentic, but this is what I do for now! To “melt” my lac, I mostly use plain ol’ rubbing alcohol, and sometimes lacquer thinner.
As noted above, for shell etching, I mix the lac with rubbing alcohol. I paint the design onto the shell. What’s special about the etching process is that the design I paint will not etch when the shell is then placed in an acid bath; the lac protects the painted areas.
As noted above, for shell etching, I mix the lac with rubbing alcohol. I paint the design onto the shell. What’s special about the etching process is that the design I paint will not etch when the shell is then placed in an acid bath; the lac protects the painted areas.
I use this acid in my classes, where speed was key. You can use vinegar, which takes longer but is easier to control.
I use this acid in my classes, where speed was key. You can use vinegar, which takes longer but is easier to control.
Here I am pulling etched shell out of the acid. You can see how much foam the process produces! You need a deep receptacle so it doesn’t spill over. You also need protective gloves. The etched shell must then be soaked in clean water to rinse away acid on its surface.
Here I am pulling etched shell out of the acid. You can see how much foam the process produces! You need a deep receptacle so it doesn’t spill over. You also need protective gloves. The etched shell must then be soaked in clean water to rinse away acid on its surface.

The next step is to clean away the lac paint with alcohol. Areas covered by the lac paint will have protected the shell surface, and they remain glossy and smooth.

I like to then stain my shells with mineral pigments mixed with lac paint or use organic dyes purely of lac or of cochineal.

Etched shell soaking in organic dye.
Etched shell soaking in organic dye.
Rubbing red ochre into the surface of an etched shell. The mineral stains the etched portions.
Rubbing red ochre into the surface of an etched shell. The mineral stains the etched portions.

Another use of lac I’m exploring is in making composite beads. From a Mimbres archaeological culture site in New Mexico, we have evidence of how people there made composite beads. There is no direct evidence they used lac to do this, but I thought I’d try it.

The first step is to thin out (by grinding) a slab of pretty stone. Then, incise notches to create strips of stone. Snap off the strips, and then snap them into roughly square sections (bead blanks).

This is steatite (soapstone).
This is steatite (soapstone).
I melted lac onto a slab and then pressed the bead blanks into the adhesive. This helped hold them in place, making it easier to drill through them. It also reduces dulling on your stone drill bit, because you hit the lac layer and not the underlying slab.
I melted lac onto a slab and then pressed the bead blanks into the adhesive. This helped hold them in place, making it easier to drill through them. It also reduces dulling on your stone drill bit, because you hit the lac layer and not the underlying slab.
Drilling.
Drilling.
I reheated the slab to melt the lac and release the bead blanks. The lac remaining on the blanks is useful for the next step.
I reheated the slab to melt the lac and release the bead blanks. The lac remaining on the blanks is useful for the next step.
The conical drill holes make it easy to align the blanks on a cactus thorn. (I used the longest prickly-pear thorns I could find; you could use wire.) The remnant lac on one side of each blank effectively glues them together, but you have to move quickly before the lac cools too much. The bead blanks will be hot, too, so you may want to use forceps or tweezers. I made a lac “handle” on the end of each thorn-thread, which made it easier to hold while rotating the section of glued bead blanks (you should keep each section to about 4 to 5 cm). I did this so that the beads wouldn’t stick to the thorn. When it was cool enough, I pulled the thorn out.
The conical drill holes make it easy to align the blanks on a cactus thorn. (I used the longest prickly-pear thorns I could find; you could use wire.) The remnant lac on one side of each blank effectively glues them together, but you have to move quickly before the lac cools too much. The bead blanks will be hot, too, so you may want to use forceps or tweezers. I made a lac “handle” on the end of each thorn-thread, which made it easier to hold while rotating the section of glued bead blanks (you should keep each section to about 4 to 5 cm). I did this so that the beads wouldn’t stick to the thorn. When it was cool enough, I pulled the thorn out.
Here are the beads being ground into a cylinder.
Here are the beads being ground into a cylinder.
Voila! A composite bead.
Voila! A composite bead.
Once you have them shaped, you can reheat to separate them into individual beads, or just leave them together as a composite bead.
Once you have them shaped, you can reheat to separate them into individual beads, or just leave them together as a composite bead.
Here are two war clubs (above and below) inspired by Indigenous examples that I made out of a nice piece of ironwood I’d been saving for the right project. With these, I used lac to fill and seal natural cracks in the wood.
Here are two war clubs (above and below) inspired by Indigenous examples that I made out of a nice piece of ironwood I’d been saving for the right project. With these, I used lac to fill and seal natural cracks in the wood.

This is a pyrite mirror (in progress) inspired by examples found at Snaketown, a famous Hohokam archaeological site. I used lac to hold the pieces of pyrite while a ground them down, and then to adhere them to the mirror backing.
This is a pyrite mirror (in progress) inspired by examples found at Snaketown, a famous Hohokam archaeological site. I used lac to hold the pieces of pyrite while a ground them down, and then to adhere them to the mirror backing.
One of my students showed me two bone awls he had found. The one on the left has lac on one end, forming an ergonomic handle. Historically, we know O’odham basket weavers used lac-handled, sharpened bicycle wheel spokes. The distal end of this one has wear patterns consistent with use in basket weaving. We don’t know the age of the awl, but it is cool to think of how far back this use of lac might go.
One of my students showed me two bone awls he had found. The one on the left has lac on one end, forming an ergonomic handle. Historically, we know O’odham basket weavers used lac-handled, sharpened bicycle wheel spokes. The distal end of this one has wear patterns consistent with use in basket weaving. We don’t know the age of the awl, but it is cool to think of how far back this use of lac might go.
Here, I’m sealing a gourd storage container with heated lac and a stone stopper. We know of similar containers from rock shelters on the Colorado Plateau.
Here, I’m sealing a gourd storage container with heated lac and a stone stopper. We know of similar containers from rock shelters on the Colorado Plateau.
Close-up of seal.
Close-up of seal.
“Hope you enjoyed learning more about me!”
“Hope you enjoyed learning more about me!”

 

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