Earth Record
Mineralogy and formation
Atlantisite is a trade name, not a mineral species. What it describes is the natural intergrowth of green serpentine and purple stichtite found almost exclusively in Tasmania, Australia.
The serpentine forms first through hydrothermal alteration of ultramafic rocks. The stichtite arrives later, crystallizing as chromium released from chromite reacts with magnesium-rich carbonate fluids. Purple veins through green host. The two-toned appearance records a sequence: ultramafic rock altered to serpentine, then chromium mobilized into carbonate form. Stichtite Hill near Zeehan, Tasmania, remains the primary source.
Stichtite: Trigonal (Rhombohedral), Space Group R-3M structure
Chemical FormulaStichtite: Mg6Cr2(OH)16CO3 . 4H2OCrystal SystemStichtite: Trigonal (Rhombohedral), Space Group R-3MMohs Hardness1.5Specific Gravity2.1-2.2 (stichtite) / 2.5-2.6 (serpentine)-composite ~2.3-2.5LusterWaxy to pearly (stichtite), waxy to greasy (serpentine)ColorGreen-PurpleIMA StatusrockIMA NumberNone (trade name for serpentinite variety; Stichtite component is pre-IMA 1910) Tasmania (Australia)
Telling it apart
Atlantisite is not a mineral species, it is a rock made of purple stichtite and green serpentine, and the main confusion is sellers presenting it as one rare crystal. The key distinction is mixed hardness and obvious two material structure: the purple stichtite is extremely soft, about Mohs 1. 5 to 2, while the green serpentine is harder, roughly 2. 5 to 4. A single needle or point dragged across different color zones will not behave the same.
Genuine atlantisite shows blotchy to veined purple patches inside green serpentine, usually opaque and waxy rather than glassy. Dyed composites often have unnaturally sharp purple boundaries or color concentrated in pits. Lepidolite and serpentine mixes can look similar at a glance, but lepidolite shows micaceous sparkle and a different feel. Because atlantisite is a trade name, ask for the actual components.
If the seller cannot say stichtite plus serpentine, they are selling a story, not an identification. The fraud risk is real because trade names hide what the holder is really buying, and a mixed rock should not be priced like a rare single species crystal.
Spotting the real thing
Atlantisite is a natural intergrowth of green serpentine and purple stichtite. Both should be present. Specific gravity approximately 2.
3-2. 5. Waxy to pearly luster.
If only one color is present, it is not atlantisite. Genuine specimens come almost exclusively from Tasmania, Australia. Check for natural intergrowth; the purple and green should merge organically, not look painted or glued.
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