aragonite
Coral's calcium carbonate
Aragonite is a mineral form of calcium carbonate, chemically identical to calcite but with a different crystal structure.
It forms the nacreous layer of mollusk shells and contributes to coral skeletons.
Aragonite crystals are often needle-like or form distinctive twinned clusters.
The mineral eventually converts to the more stable calcite over geological time.
Iridescent inner shell coating
- iridescenceColor shift from interference
- pearlMollusk-formed gemstone
- shellHard outer covering
- molluskSoft-bodied invertebrate, often shelled
abalone · nautilus · oyster · mussel · bivalve · gastropod · luster · sheen
Naturally formed crystalline solid
- sedimentaryFormed from deposited material
- limestoneCarbonate sedimentary rock
- marbleRecrystallized limestone rock
- metamorphicUndergoing structural change
cement · precipitate · evaporite · geochemistry · formation · deposit · nodule · concretion
Marine skeletal formation
- reefUnderwater rock or coral formation
- skeletonInternal supportive framework
- biogenicProduced by organisms
- seashellMollusk's discarded exoskeleton
seafloor · ocean · carbonate · dissolution · acidification · saturation · warm water · tropical
Light-dispersing, multicolored
- acicularNeedle-shaped in form
- twinnedMade into a pair
- tabularOrganized in grid format
- columnarShaped like a pillar
needlelike · habit · lattice · cleavage · symmetry · facet · transparent · translucent
Hanging cave mineral deposit
- stalagmiteUpward-growing cave deposit
- flowstoneCalcite sheet from seepage
- dripstoneCave mineral deposit
- frostworkOrnate ice crystal formations
soda straw · column · karst · cavern · grotto · underground · precipitation · Carlsbad
mother-of-pearl
Iridescent inner shell coating
- iridescenceColor shift from interference
- pearlMollusk-formed gemstone
- shellHard outer covering
mollusk · abalone · nautilus · oyster · mussel · bivalve · gastropod · luster · sheen · opalescence
mineral
Naturally formed crystalline solid
- sedimentaryFormed from deposited material
- limestoneCarbonate sedimentary rock
- marbleRecrystallized limestone rock
metamorphic · cement · precipitate · evaporite · geochemistry · formation · deposit · nodule · concretion · replacement
coral
Marine skeletal formation
- reefUnderwater rock or coral formation
- skeletonInternal supportive framework
- biogenicProduced by organisms
seashell · seafloor · ocean · carbonate · dissolution · acidification · saturation · warm water · tropical · calcareous
prismatic
Light-dispersing, multicolored
columnar · needlelike · habit · lattice · cleavage · symmetry · facet · transparent · translucent · vitreous
stalactite
Hanging cave mineral deposit
- stalagmiteUpward-growing cave deposit
- flowstoneCalcite sheet from seepage
- dripstoneCave mineral deposit
frostwork · soda straw · column · karst · cavern · grotto · underground · precipitation · Carlsbad · spelunking
- mineralsquartz, marble, granite, limestone, sandstone
- limestonecalcium carbite, chalk, dolomite, marl, travertine
- reef materialscoral, limestone, dead coral
- calcium compoundscalcium chloride, calcium phosphate, quicklime, chalk, calcium carbide
- calcium mineralsgypsum, apatite, anhydrite, chalk, travertine
- carbonate mineralsmagnesite, siderite, malachite, azurite