This is the 7783rd most frequent Spanish word.
macizo
Solid; sturdy; massif (geological formation).
Here, "macizo" means solid or made entirely of the specified material, emphasizing the composition of the ring.
El anillo es de oro macizo.
The ring is made of solid gold.
In this sentence, "macizo" refers to a geographical feature, specifically a compact group of mountains or a mountain massif.
El macizo montañoso en esta región es impresionante.
The mountain massif in this region is breathtaking.
Here, "macizo" is used colloquially to describe something sturdy, strong, or impressive in quality.