mineral
White turquoise (likely howlite)
Howlite, Ca₂B₅SiO₉(OH)₅; visually similar white magnesite is another possibility
AI-generated identification · may be incorrectOpaque white, polished stone with dark branching matrix and vitreous-to-waxy luster. Howlite is monoclinic, Mohs hardness 3.5; the photo alone cannot confirm the mineral identification.
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Physical properties
Opaque white, polished stone with dark branching matrix and vitreous-to-waxy luster. Howlite is monoclinic, Mohs hardness 3.5; the photo alone cannot confirm the mineral identification.
Formation & geological history
Howlite forms as a secondary borate mineral in evaporite-rich sedimentary deposits, commonly in arid regions. Its age varies by deposit.
Uses & applications
Used for carvings, beads, and cabochons; it is often dyed to imitate turquoise. Not generally used in construction.
Geological facts
The distinctive dark webbing is natural matrix; similar patterns occur in both howlite and magnesite.
Field identification & locations
Common sources include California and Nova Scotia. A gemologist can distinguish lookalikes with hardness, density, or laboratory tests; avoid scratch-testing a finished cabochon.
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Other mineral specimens
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Gneiss or Mica Schist with Garnet
Metamorphic
Sandstone (with potential mineral staining/concretions)
Arenite (SiO2 based)
sedimentary
Tumbled granite
Granite, a coarse-grained felsic intrusive igneous rock
igneous
Epidote
Epidote | Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH)
metamorphic
Pegmatite with Tourmaline and Quartz
Igneous Pegmatite
igneous
Granite
Granite (Phaneritic intrusive igneous rock)
igneous