Pentagonal and Heptagonal shaped drill holes in rock and how they were made in prehistory.
In 2017, when I first saw the below ancient 5-point star shaped hole in granite rock, I was confused on how the inward curved sides leading to a sharp point were created.
Nothing in my lapidary arsinal at the time could recreate such a difficult drill hole. After months of researching all known stone cutting technologies, I found ultrasonics in 2018 through the jewelry and lapidary industry where I reside.
(Above left) ancient 5-point star shaped drill hole in granite with inward curved sides leading to a sharp point found in Massachusetts. (Above right) 5-point star shaped drill holes in granite using ultrasonics and a shaped metal tube. The inward curved sides of the created star holes are the same as the ancient drill hole in Massachusetts.
To shape a metal tube with evenly spaced points a drawplate (not shown) is needed for shaping the tube. Forging sheet metal into a star shape as shown in the star cookie cutter (below left) is the incorrect way to make a tube for ultrasonic drilling.
Once the metal star shaped tube is created from a drawplate, the tool is ready to be attached to the ultrasonic machine. A 5-point star shaped metal tube with inward curved sides will drill a hole in rock with 5-points and curved inward side walls.
(Below) an example of the shapes made by a 5-point drilling tube. A 5-point star drilling tube will drill both a 5-point star hole and a 5-sided pentagonal hole in rock.
The above image is an example of a 5-point star tube opening to a 5-sided tube (pentagon). A 5-point star drilling tube will create both a star and pentagon hole in rock.
(Below) a faceted basalt hexadecagon (16 sides) with 3 ultrasonic drill holes having different shapes while using one shaped tool.
(Above) 3 shaped drill holes created by using only one drilling tube. At the 12 o’clock position is a shallow star drill hole showing the shape of the tube. The drill hole to the right still has a star shape while drilling deeper into the basalt. As the drilling tube drills even deeper into the rock, the outside entry hole loses its star shape and becomes 5-sided or pentagonal.
The above images of a 5-point star hole and 5-sided pentagonal drill hole were made using one shaped drilling tube.
(Below) looking into the pentagonal hole, you can see the transition. The back of the hole shows a clean 5-point star, while the entrance is pentagonal in shape. One tube makes both shapes in stone.
5-point star shaped drill holes are often accompanied by holes with 5-sides. One drilling tube makes both shapes in stone.
(Below) the ancient, shaped bore holes found in the Grand Canyon show a slight star shape (with 5 lobes) and a slight 5-sided pentagonal shaped hole.
These 2 shaped drill holes are hallmarks of ultrasonic drilling. Shaped holes are ultrasonically created.
(Below) 2 shaped drill holes in rock from Wales, UK. One hole has a 5-point star shape and the other has a pentagonal shape. Both holes were made by the same tube.
Pentagonal and star shaped holes showing heavy wear are extremely ancient. When first drilled they would have looked clean and crisp in outline.
(Below) Pentagonal and star shaped holes created by the same drilling tube (Dartmoor UK).
Star holes are unique because with thousands of years of erosion the star shape is still visible. Ancient drill holes that are clean and crisp have been protected from the elements, giving us a look into the past advanced drilling capabilities used in prehistory.
(Below) a rock from New York containing a 7-point star shaped drill hole and a 7-sided drill hole (heptagon).
One drilling tube made both shapes in rock. Understanding how these holes were made helps humanity better understand past capabilities of ancient builders.
Hopefully, people today will want to learn how these rock machining techniques were once mastered by ancient advanced civilizations in America (pre-Younger Dryas, in the Pleistocene, over 10,000 years ago).
When hunting for ancient drill holes in America, look for precision made drill holes in the shape of a star or a drill hole with flat sided internal walls (pentagonal and heptagonal).
If you come across a 5-or-7-pointed star shaped drill holes, you may also come across heptagonal and pentagonal shaped holes. All are created by ultrasonics.
(Below) inspired by advanced technology used in ancient times, the basalt hexadecagon was drilled with a round hole near the stone’s edge. This cannot be done with today’s spinning diamond core drills.
Tube drilling using ultrasonics allows for precise machining of rock in ways conventional techniques fail. Using ultrasonics not only gives us a glimpse of ancient stone machining, it can also advance our ability to carve rock for jewelry purposes.
Jewelry created using the same ancient, advanced stone cutting techniques is known as jewelry of the gods.
If precision stone machining created in prehistory is labeled as work of the gods, then anyone using or teaching this technology today is a god, at least in the eyes of those not in the know.
If you want to learn these god-like advanced engineering feats made in stone, you can learn through the Ultra Arky group. Classes and group field trips are being planned in 2026 for 2027 with events you can participate in and become overwhelmingly enlightened.