Apache tears (marekanite or obsidianites) are smoky, dark gray, gray-brown, or black indented tear-shaped, rounded, or subangular small obsidian balls, pebbles, or nodules measuring up to 2 inches in size that often occur within perlite masses.
Obsidian is volcanic rock, not a mineral crystal, formed by the rapid cooling of highly viscous rhyolitic magma that prevents mineral crystallization. However, people who sell these nodules as inexpensive semi-precious stones often call them crystals or minerals. It is incorrect.
Learn more about Apache tears, including the origin of the name, what they are, and how they form. We will also discuss their prices, uses, and a lot more.
Quick facts and properties
- Names: Apache tears, obsidian nodules, obsidianite, marekanite, or obsidian balls
- What is it? Small, water-drop, spherical, or subangular obsidian glass balls often occur as cores in some perlite masses.
- Color: Smoky, brown, black, or dark colored
- Mohs scale hardness: 5-5.5
- Size: ≈0.2-2 inches (0.5 to 5-1cm)
- Specific gravity: 2.3 – 2.6
- Texture: Glassy or vitreous
- Fracture: conchoidal
- Crystal system: Amorphous
- Optical properties: Translucent to semi-translucent when polished. Some show chatoyancy.
- Composition: 70-75% silicon dioxide (SiO2), water >2%, with the remainder varying percentages of oxides of aluminum, magnesium, potassium, sodium, sulfur (trioxide), and iron, depending on the source. Also, it may have other inclusions like magnetite and hematite, which give black and reddish-brown colorations.
What are Apache tears?
Apache tears are dark-colored to black tear-shaped, sub-rounded, or spherical obsidian volcanic glass nodules, pebbles, or balls measuring no more than two inches with indented surfaces. They belong to the subalkaline series corresponding to rhyolitic composition in the TAS classification of volcanic rocks.
Also known as obsidianites or by their lithological name, marekanite (named after Marekanka, near Okhotsk, Siberia, Russia, a place of their first discovery), these obsidian balls show a conchoidal fracture, semi-transparent to translucent, with a Mohs scale hardness of 5-5.5.
Unlike the surrounding perlite matrix, obsidian balls have a glassy texture and perlitic and have lower water content, i.e., less hydrated. Sometimes, the presence of silky striations makes them chatoyant.
Microscopic observation of some obsidian balls reveals subhedral magnetite inclusions and other randomly dispersed microphenocrysts. However, amphiboles have a subparallel arrangement, with the outer part having rare anhedral apatite crystals.
The microscopic inclusions (felspar fibers) may make some Apache specimens show chatoyancy or cat’s eye effect when cut correctly in cabochon. Those that show a cat’s eye effect have more value in the gemstone market.
Name origin: Apache tears legend or story
Obsidianite gets the Apache tears from a traditional legend of the Apache tribe whose 75 worriers, outnumbered and facing imminent defeat by the U.S. calvary in the 1870s, rode their horses off the Apache Leap Mountain (now overlooking Superior, Arizona) to their death to avoid surrendering or capture.
When the family and wives of the warriors heard about their tragic deaths, they cried, and the legend says that their tears turned into obsidian gemstones or obsidianite rocks upon hitting the ground. However, in geology, Apache tribe legend is not how these stones formed.
Obsidian balls occurrence
These obsidian balls are widespread throughout the Cenozoic volcanic terrain in the western United States, some exposed from eroded tuff beds. Some are still intact within the surrounding perlite matrix; others are exposed by weathering and fracturing owing to their nature, characterized by microscopic fractures.
Some places to find Apache tears include Superior (Pinal County) and Maricopa in Arizona, Mule Creek, East Grants Ridge in New Mexico, Scotty’s Junction Rockhounding Area, and Fish Lake Valley in Nevada. Also, they occur in California.
These obsidian nodules also occur in Marekanka, near Okhotsk, Siberia, Russia, Mexico, Hungary, and Cerro Tijerina in Nicaragua. They are often known as marekanite in Russia and Mexico, while in Hungary, Tokay lux-sapphire.
How do Apache tears form?
Apache tears form from the rapid cooling of silica-rich rhyolitic lava flows and domes or ash-flow tuffs. Differential cooling, alkali content, and water content likely influence the formation of obsidian balls and surrounding perlite masses or matrices.
Let us talk briefly about perlite and obsidian before concluding on formation. It should make everything much clearer.
Perlite is a light gray to dark gray amorphous volcanic glass with concentric cracks that break off like onions to form pearly-like pieces. It most probably originates from obsidian hydration as it differs from obsidian by water content, i.e., 2-5% vs. less than 2%, while pitchstone, its counterpart, has 5% or more H2O.
Studies [1] have shown that these obsidian balls and vesicular texture perlite evolved together. They have similar chemical and mineralogical compositions and form from the same silica-rich melt. Also, they both have subparallel crystals and minerals suggestion formation before solidification.
Also, studying the glass of marekanite and perlite shows that their glass is homogenous save for the outer shell due to hydration. This revelation may indicate hydration happens after solidification.
Therefore, it is likely that Apache tears form by rapid cooling or quenching of rhyolitic magma with partial hydration, resulting in an obsidian core/ball and surrounding perlite matrix. Complete hydration will create perlite without cores.
Uses of Apache tears
These semi-precious stones or gemstones are collected and sold as rock specimens to rockhounds and for lapidary, i.e., shaped and polished (including by tumbling) to make decorative items like cabochons, especially those displaying chatoyancy. Some may also be faceted or used to make jewelry like bracelets, necklaces, earrings, and pendants.
In ancient times, they made small stone implements such as arrowheads, especially some Native Americans, especially the Apache Indians in the western part of the U.S., where these stones are predominant.
Lastly, Apache tears have metaphysical, spiritual, religious, and astrological properties. However, our perspective is from a geological point of view.
What are Apache tears worth?
Apache tears will cost as little as USD 0.5 to 3 dollars per piece, with a pound going for 20-50 dollars, depending on the size, weight, appearance, and other properties/factors. An extra-large rock may go for as high as $20.
However, Untumbled, raw Apache tears may cost less, and buying in bulk will make a saving.
References
- Mrázová, & Gadas, P. (2012). Obsidian balls (marekanite) from Cerro Tijerina, Central Nicaragua: Petrographic investigations. Journal of Geosciences, 43–49. https://doi.org/10.3190/jgeosci.086
- Manutchehr-Danai, M. (2009). Dictionary of gems and gemology (3rd ed.). Springer.
- O’Donoghue, M. (ed.), (2006). Gems: Their sources, descriptions, and identification (6th ed.). Butterworth-Heinemann
- Romaine, G. (2020). Rocks, gems, and minerals (3rd ed.). FalconGuides.