So often I get the question “what is a gold crystal?” In layman's terms, it’s the triangles and cubes that appear on a gold specimen. But that answer does not do gold crystals any justice and there is so much more to the world of gold crystals and gold specimens. This brief article will break it down in simple terms and make you an expert at understanding and identifying gold crystals.
Gold, in any form, is a very rare metal. Only about 2% of all gold in the world is in the form of a gold nugget. Now consider that of the 2% that is classified as “nugget gold”, only about 2% of that has crystal formations. So about 0.04% of gold is in the form of gold crystals. They are extremely rare and are in a category all their own.
Viktor M. Goldschmidt’s Atlas der Kristallformen (1918) documented 116 different and well formed gold crystals and crystal groupings. Goldschmidt’s descriptions are correct and have been observed either singly, or in combination on gold crystals. But despite his detailed work and numerous drawings, there are really only a few distinct groups that are most commonly found in gold crystals (keep in mind I use the word "commonly" loosely and as we've discussed, gold crystals are very rare).
The most common gold crystals in the cube family are the cube with six faces, octahedrons with eight faces, and rhombic dodecahedrons which has 12 faces. Less common among gold crystal specimens are the tetrahexahedron, trisoctahedron, hexterahedron each with 24 faces, and finally the hexoactahedron with 48 faces. That's a lot of big words and I promised you this article would break it down in simple terms. Just remember the first two...cubes and octahedrons. Most gold crystals in the cube category are a variation of these two shapes.
As with the cube diagram, the most common gold crystals in the Pyramid family are the first three examples. The trigon (trigonal) with four faces, the ditrigone (ditrigonal) with seven faces, and the tetragon (tetragonal) with five faces. The majority of gold crystals in the pyramid family are trigons or a slight variation, so just remember the word trigon.
Another very interesting formation that can occur with gold crystals is called Spinel-Law Twins, also referred to as Spinel Twins. Its a form of contact twinning, in which two octahedral crystals twin at the base. Named after the mineral Spinel, which often exhibits this form of twinning. This happens more frequently with octahedral crystals but can also be seen in other formations. Think about spinel twins as a single crystal that has a mirror duplicate crystal attached to it. Two crystals that form from the same base.
- Starts with an octahedron.
- One face is distorted resulting in a flattened form with triangular shape.
- The gold crystal is twinned on the octahedral space.
Examples of defined gold crystals
Example A) shows very well defined cube gold crystals.
Example B) has octahedron crystals on the middle of the specimen and a very pointed chevron gold crystal on the left side of the specimen.
Example C) is a mass of octahedron and trigon gold crystals that cover the entire surface.
Example D) is the basic form of a spinel twin. Remember, two crystals that form from the same base.
Other interesting formations
What keeps gold interesting for me is that it seldom follows the rules. The photos above are some great examples of defined and faceted gold crystals but that’s just the basics. Gold crystals can be, and often are, so much more dynamic than just the basics. Be it ribbons, feathers, wires or cubes; gold crystallization can take on many forms. Every piece is a unique and a one of a kind specimen. The following are examples of gold crystals that break the rules of traditional crystals.
Here we have two examples of a gold crystal formations that are referred to as dendritic. A dendritic gold crystal is composed of branching tree-like formations and often resembles a leaf or fern with a repeating pattern. Both examples pictured below have a dendritic form but are very different and are from very different locations. The gold specimen on the left is very thin and fragile and the gold is "pressed" and fanned out. The gold specimen on the right is quite different and has a thick nugget quality but is still very much a member of the gold crystal family with it's fantastic dendritic form.
This gold specimen is very thin and fragile and the gold is "pressed" and fanned out.
This has a thick nugget quality but is still very much a member of the gold crystal family with it's fantastic dendritic form.
Hoppered or hoppering gold refers to a unique formation in which the crystals form and exhibit a terraced and often times indented structure penetrating towards the center as shown on the top of the gold specimen on the left. Take a closer look at this gold specimen. As is often the case with these rare treasures, the gold has many different formations and the body is covered with very well defined cubes, trigons, and octahedron gold crystals while the top of the specimen has taken a completely different crystal formation and is two large and hoppered chevron crystal. The photo on the right is a good example of wire gold formations, although very rare, these gold crystals are composed of long, slender, curvy, interwoven wires of gold.
Exhibits a terraced and often times indented structure penetrating towards the center.
These gold crystals are composed of long, slender, curvy, interwoven wires of gold.
Striated gold formation is gold crystals that exhibit parallel line growth or grooves on crystal faces. The example in the photograph on the left is a very good example of a gold crystal comprised entirely of striated gold. Ribbon gold, shown in the photograph on the right, is often attached to a gold crystal specimen in one form or another and is a very thin band of gold that's been pressed naturally by the elements.
A gold crystal comprised entirely of striated gold.
Ribbon gold is often attached to a gold crystal specimen in one form or another and is a very thin band of gold that's been pressed naturally by the elements.
Can a Gold Crystal Specimen have it All?
Ready to test your knowledge? The example below is a fascinating and mesmerizing gold crystal specimen from the Round Mountain Mine in Nye County, Nevada. We call him the dinosaur. Take a good look at it and see if you can identify the different crystal formations.
How'd you do? Here's what we picked out from this beautiful specimen.
Here's the other side of the specimen just so you can see both and compare the uniqueness of both sides. This side has way more striated long ribbon gold and even has rows of neatly coordinated chevron crystals on the individual bands. It has less of the larger well defined gold crystals, but it's certainly no less interesting.
Unreal isn't it? The dinosaur and so many other unique gold specimens are the reason we stay so interested in the subject of gold and natural gold specimens...they are just so fascinating, precious and rare. Now that you are educated on gold crystals, we encourage you to keep checking back at The Gold Museum periodically and touring through our vast collection of rare treasures. We promise to keep amazing you with sourcing the worlds finest gold specimens, whether you're a collector, investor, or just an admirer.