The key point
Separate the age of host rock, mineral formation, and human discovery, and compare published models.
Three timelines that should not be confused
The age of volcanic host rock, the timing of mineral growth within it, and the modern history of finding and naming a gemstone are different questions. A date describing rock formation does not automatically date a particular cabochon. Likewise, a twentieth-century discovery account says nothing about when its minerals crystallized.
A recent model
The abstract of a 2024 study describes Larimar in veins and cavities of altered Cretaceous basalt. It links formation to alkali-rich fluids below 170°C that later mixed with meteoric water. The authors use mineralogical and geochemical evidence to discuss changes in the formation environment. This is a scientific model for studied material, not a dated certificate for individual merchandise.
Why older summaries can differ
A 2017 host-rock study discussed altered basalt, filling of open spaces, replacement of organic material, and a proposed formation environment. Its model included higher temperatures than the later study. These papers should be read in their own sample and methodological context, rather than combining numbers from separate models into one supposedly exact recipe.
Is Larimar petrified wood?
The 2017 paper discusses replacement of organic material and proposes the term xilolarimar in that context. That does not justify describing every polished Larimar stone as petrified wood. If a specimen is sold specifically as a replacement of wood, ask what observable or documented evidence supports the description for that specimen.
How to handle an exact-age claim
Ask for the cited geological work, what was dated, the method used, and whether the statement concerns host rock or the mineral itself. Without that context, a precise age on a product card can suggest more certainty than the evidence supports. Our site does not assign exact formation ages to individual stones.
Sources & scope
Our summary uses the publicly available abstract. Full paper DOI: 10.1016/j.jsames.2024.104949. It is a formation model, not a direct age determination for retail stones.
An earlier host-rock and formation interpretation, including discussion of organic replacement; it should not be generalized to every Larimar specimen.
Our initial library was developed with AI assistance. Product claims require separate item-specific evidence. Read our editorial standards.