Arizona Ruby

Arizona Ruby is a trade name for chrome pyrope garnet found in northeastern Arizona, particularly on the Navajo Nation around the Four Corners. It is closely tied to the well-known anthill garnets — small, deep red crystals that ants carry to the surface while excavating their nests.

Like Cape Ruby, the name references the stone's ruby-red color rather than any relationship to corundum. The chromium content gives Arizona pyrope an unusually vivid, slightly purplish red.

Most stones are small but very clean, making them a charming and affordable collector and jewelry gem.

These garnets originate in the mantle and are carried toward the surface in kimberlite and related volcanic diatremes such as those of the Navajo volcanic field (for example, Garnet Ridge). Pyrope is a high-pressure mineral that crystallizes in peridotite and eclogite at depth.

When the volcanic host rock weathers, the resistant garnets accumulate in soil and surface gravels. Harvester ants bring the small crystals up as they dig, leaving them scattered on and around anthills — hence the nickname anthill garnet. Collectors simply pick them from the surface.

Arizona Ruby appears as small, rounded to dodecahedral, transparent deep red grains with bright luster.

• Hardness: 7-7.5.
• Streak: white.
• Optic character: singly refractive (isometric).
• Fracture: conchoidal, no cleavage.

The chrome content can give a faint red flash under a spectroscope (chromium absorption). Distinguish from spinel and ruby by single refraction and from almandine by its purer, less brownish red. Sizes are usually under a carat, which itself is a clue to anthill-sourced material.

Arizona Ruby is cut into small faceted stones for rings, earrings, and pendants, and is a popular Southwestern and Native American jewelry gem. Because crystals are small, it is often used in clusters or accent settings.

It is affordable and durable. In metaphysical circles red garnet is linked to energy and grounding, though such uses are not scientifically supported.