This exceptionally rare and precious gemstone is a an extremely rare form of ruby called a “Record Keeper Ruby.” These ultra rare rubies form naturally when triangular growth layers, or "trigons," develop on the surface of corundum crystals during their millions of years of growth, caused by specific, persistent crystal structure defects. These can be raised (stepped) or indented (etch pits), indicating a natural, unpolished surface where the crystal's trigonal symmetry is expressed. 

Naturally forming “record keeper” ruby crystals are extremely rare, the vast majority of the examples found for sale online have actually been low quality dyed rough ruby crystals that have been hand etched with a rock cutting tool or by a gemstone cutter. Real record keeper rubies are very rare and valuable, so you can typically spot a fake when a seller has many listed for a very low price. This is usually a strong indicator they are hand etching regular ruby crystals. This record keeper ruby is 100% natural forming. The triangular shape formed due to the crystals internal trigonal atomic crystal structure during natural growth processes. This ruby is also completely natural, untreated, and of exceptional quality.

Adding to this rubies incredible rarity is the location in which it was found. This ruby was found in Rock Creek, Montana, USA. Montana is known for producing corundum in a wide variety of colors, but the area typically lacks the chromium required to make corundum which falls in the specific red category of rubies. Rubies have been found in Montana but are so rare they are considered priceless. The Gemological Institute of America did a well published study where they mined 400 kilograms of corundum from Rock Creek, and only found 29 rubies, none of the rubies they found were record keeper ruby crystals, which makes record keeper rubies such as this one, from Rock Creek, even more Rare! This ruby does fall well within the required limits to be called a ruby under GIA standards. It has a red chromium caused base hue with very slight pink and purple undertones which can be found in virtually all of the Montana rubies found to date. This unique coloring is something knowledgeable collectors look for when identifying rubies from this region.

My husband is a geological engineer and forensic gemologist who was working on a contract in the the Rock Creek area and got the rare opportunity to purchase this ruby directly from the original prospector who found it. The ruby was discovered in the early to mid 1990’s and my husband purchased it in 1999. It has been stored safely ever since and is in the same perfect condition as the day it was found.


This ruby measures 12x12 mm and is 3.5 mm thick. The weight is 5.575 carats. This is a great size for use in a large ring, and will have many other setting options. We originally planned on setting it in a pendant with a gold bezel and a row of diamonds set into the bezel like a spaced halo. Unfortunately for me too many other projects came firs and we never made the pendant.


This record keeper ruby is of exquisite quality and priceless value. The trigons are very large in comparison to the face of the stone. This makes them very bold and easy to see. The triangles of the trigons also project from both sides of the stone which is also extremely rare and desired. The trigons have perfect triangular symmetry atop the rubies natural hexagonal crystal shape. Lastly the trigons are of extremely large size, filling the entire surface with the trigonal crystal growth to the horizon on all 3 points (on both sides).

I am open to reasonable offers on all of the items I sell. Especially if you’re purchasing multiple items.

This is the rarest and one of the most interesting gemstones I have ever listed for sale on eBay!