Black onyx and black cubic zirconia are different materials. Onyx is a variety of chalcedony, a form of quartz. Black CZ is man-made zirconium oxide. Both can look deeply black in a ring, so color alone won't tell you which one you're buying. The useful comparison comes from three parts of the listing: the material label, the treatment disclosure, and what each measurement actually describes.
Start with the material you want, then check how clearly the seller describes it. A natural material can be treated, and a man-made stone can be sold without further treatment. Those distinctions are more useful than choosing from color alone.
Two names, two different materials
Onyx is a variety of chalcedony, which is a microcrystalline form of quartz, characterized by parallel layers of color. As GIA's explanation of onyx and black chalcedony notes, much of what's sold as black onyx is chalcedony that has been dyed black, while naturally black material is rare. That's a general market practice, not a verdict on any particular ring. A label reading "black onyx" names the material being sold; it does not, by itself, disclose dyeing or provide independent identification.
Cubic zirconia is something else entirely. GIA's introduction to simulants and imitation gem materials describes CZ as man-made zirconium oxide that can be produced in a range of colors, black among them. Black CZ is not a kind of onyx. It isn't a mined black diamond or a lab-grown diamond either. It's its own material.
Identity, creation and treatment are separate questions
A stone description is easier to read when you split it into three questions:
- Identity: what substance is the stone?
- Creation: did it form in nature, or was it made?
- Treatment: was anything done to change it, such as dyeing?
The Medieval Armor Cross ring shows why the split matters. Its raised cross carries black cubic zirconia accents, and the seller confirms those stones are man-made and not treated. "Not treated" answers the treatment question; it does not make CZ a naturally occurring stone. "Man-made" describes how it was produced, rather than grading its quality.
The Black Onyx Dragon Claw ring lists its stone as black onyx, and the listing doesn't state whether the stone is treated. The missing disclosure supports neither a dyed nor an untreated claim. If treatment matters to you, ask before you order. The same goes for any listing where a tag or filter seems to disagree with the written stone description.
The two rings side by side
Both rings are listed in solid .925 sterling silver, with black onyx at the center of one and black CZ accents in the other. The table combines current product specifications with Gothicrock's confirmation of the CZ creation and treatment details. These are seller statements, not an independent laboratory report.
| Specification | Black Onyx Dragon Claw Ring | Medieval Armor Cross Ring |
|---|---|---|
| Metal | Solid .925 sterling silver | Solid .925 sterling silver |
| Stone material | Black onyx | Black cubic zirconia (accents) |
| Creation | Not stated | Man-made (seller-confirmed) |
| Treatment | Not stated | Not treated (seller-confirmed) |
| Stone dimensions | Approx. 15 × 20 mm | Not stated |
| Stone weight | Approx. 35 carats | Not stated |
| Ring face dimensions | Not stated | Approx. 22 × 31 mm |
| Whole ring weight | Approx. 36 g | Approx. 16 g |
| Sizing | Selectable US ring sizes | Selectable US ring sizes |
"Not stated" marks a missing disclosure; "not treated" records the seller's affirmative answer. The approximate measurements refer to these two products, not to every onyx or CZ ring.
What the numbers actually measure
The 15 × 20 mm figure on the onyx ring is the size of the stone. The 22 × 31 mm figure on the armor ring is the listed ring face measurement. Those numbers describe different things, so they can't tell you which ring has the larger black stone. Compare stone to stone and face to face. For these two rings, neither pair is available for both.
Weight works the same way. A carat is a unit of mass, not size; one metric carat equals 0.2 g. So "approx. 35 carats" describes how much the onyx weighs, not how wide it is. The ring weights, on the other hand, are a like-for-like pair: the claw ring is listed at about 36 g and the armor ring at about 16 g, so the claw ring has the higher listed overall weight.
The 36 g figure is listed as ring weight, not a separate silver-component weight. Use it to compare the finished pieces; it does not establish how much silver the ring contains.
Inspect the design behind each specification
Photos help you judge the look, but they can't confirm what a stone is made of. Use them alongside the written specifications. If you're still weighing claw, cross or skull designs, our guide to gothic ring styles covers design families and fit.
Ring aus .925 Sterlingsilber mit Drachenkrallen und schwarzem Onyx
A listed black onyx center framed by sculpted claws and axe details, with stone dimensions and carat weight supplied.
View details and sizes
Mittelalterlicher Rüstungsring mit Kreuz aus 925 Sterlingsilber
A black CZ cross on linked silver armor panels. Check the gallery, listed face dimensions and current US sizes.
View details and sizesQuestions to ask before you order
- What material does the listing name for the stone, in writing?
- Does it say whether the stone was made or formed in nature, and whether it was treated? If not, and it matters to you, ask.
- Does each dimension describe the stone or the whole ring face?
- Is a weight given in carats for the stone or in grams for the whole ring?
- Is your US size currently offered for that design?
Once a listing answers the questions you care about, the choice comes down to the design you want to wear. Browse our gothic rings collection and read each stone description the same way.
