About this stone
Color
TanCreamBrownGray
Origin
MoroccoUSAMadagascarChina
Mohs hardness
5–7 (varies by mineralization)
Treatment categories
Natural
Industry-standard treatment
Natural — fossils are organic remains replaced by silica, calcite, or other minerals over millions of years
Mineral chemistry
Variable — typically silicified or calcified preservation of organic remains (shells, bone, plant)
Crystal system
Mixed
Stone family
Organic fossil
Common cuts
Round
Common sizes
6mm8mm10mm
Care notes
Care depends on mineralization (Mohs 5–7). Mild soap and soft cloth; avoid ultrasonic for porous material.
Related stones
Petrified Wood, Fossil Coral, Ammonite, Amber
Frequently asked questions
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Are fossil beads real fossils?
Yes. Fossil beads are cut from material in which ancient organic structures — shell, coral, bone, or wood — have been preserved by mineral replacement. Over geological time, mineral-rich groundwater filled the spaces left by decaying organic material with calcite, aragonite, silica, or pyrite, preserving the original structural pattern. The bead is a cross-section of that preserved structure. The specific organism (ammonite, orthoceras, coral, turritella) and the replacement mineral should be disclosed specifications table. -
What's the difference between fossil coral and agatized coral?
Both are fossilized coral colonies preserved by mineral replacement. The distinction is the replacement mineral: fossil coral is the general term and may be calcite- or aragonite-replaced (softer, Mohs 3–4); agatized coral is silica-replaced and is essentially chalcedony in the shape of the original coral structure (harder, Mohs 6.5–7). Agatized coral takes a higher polish and is more durable for daily wear. the listing should specify which type a given strand contains. -
How durable are fossil beads for daily wear?
Durability depends on the replacement mineral. Silica-replaced fossils (agatized coral, petrified wood, turritella agate, gembone) are Mohs 6.5–7 and suitable for any jewelry application including rings. Calcite- or aragonite-replaced fossils (most ammonites, orthoceras, many fossil corals) are Mohs 3–4, comparable in softness to lapis or turquoise — best for earrings, necklaces, and bracelets that avoid frequent impact; avoid ultrasonic and steam cleaning. -
Are fossil beads treated?
Dakota's current fossil bead inventory is sold natural — the mineral replacement is the geological process that created the material, not a post-cutting treatment. In the broader fossil bead market, some material is dyed (most often pale fossil coral, to deepen color) or stabilized (low-grade ammonite with internal fractures). When treatment is present, it should be disclosed — confirm before buying if a strand doesn't specify. -
What sizes does Dakota carry?
Current active fossil bead inventory centers on 8mm and 10mm rounds. Full size and shape availability is filterable in the grid above; designers replenishing an existing design can confirm exact strand specifications on each listing.