Earth Record
Mineralogy and formation
Cavansite-stilbite is a natural combination of two zeolite-group minerals that form together in the Deccan Traps basalt flows of India. Cavansite, the vivid blue mineral, was first discovered in 1967 and named for its composition (calcium vanadium silicate). Stilbite, the white to peach-colored companion, is one of the most common zeolites.
The combination is highly prized by collectors: the intense blue of cavansite rosettes contrasting with the soft, bow-tie shaped stilbite crystals creates a visual harmony that is both striking and soothing. The two minerals form in the cavities (vugs) of ancient basalt lava flows, where mineral-rich waters deposited them over millions of years.
Mixed (Orthorhombic + Monoclinic) structure
Chemical FormulaCa(VO)(Si4O10).4H2O + NaCa4(Si27Al9)O72.28H2OCrystal SystemMixed (Orthorhombic + Monoclinic)Mohs Hardness3Specific Gravity2.20-2.30LusterVitreous to pearlyColorBlueIMA Statustrade_nameIMA Number1967 (pre-IMA numbered format) India (PuneMaharashtra)
Telling it apart
Cavansite on stilbite is valuable enough that treated blue coatings and glued assemblies show up in the market. The confirming step is check whether blue cavansite rosettes sit naturally on stilbite without glue lines or color bleed. Sellers can lean on color, trade names, or locality mythology, but that one check separates the real material from the easy substitute. Cavansite Stilbite has its own physical signature in the hand and under magnification, whether that means unusual density, a true internal growth pattern, a natural host matrix, or evidence of locality and structure.
Fraud or simple sloppiness matters differently here than it would for a generic tumbled stone. The price gap between natural Indian combinations and altered material is real. A buyer paying for Cavansite Stilbite is paying for a specific geological story, not just a similar color. The blue mineral identification is the price driver, and swapping pentagonite or dyed zeolite for cavansite changes the specimen fundamentally.
Spotting the real thing
Cavansite: vivid blue crystal clusters (distinctive electric blue) on white stilbite matrix. Specific gravity 2. 20-2.
30. Mohs 3-4 (soft). The blue is intense and natural.
If the blue looks painted or is only surface-deep, it is not genuine. Most cavansite-stilbite comes from Pune, India. The combination of electric blue on white is highly distinctive and rarely imitated because the natural material is affordable.
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