font . An archaic term for a stream or a spring, fountain, or source of a stream; it forms part of place names, such as Chalfont.
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genal spine . A spine extending backward from the genal angle of the cephalon of a trilobite, produced on the outer posterior margin of the free cheek.
belonosphaerite (bel''-o-no-sphae'-rite). An obsolete term for a spherulite whose minerals are in radial arrangement.
stratiform nickel-copper deposit . A mineral-deposit type characterized by stratiform nickel and copper sulfide minerals in the basal portion of layered mafic-ultramafic intrusive complexes. Syn: Stillwater-type nickel-copper deposit.
rutheniridosmine (ru''-then-ir''-id-os'-mine). A metallic white hexagonal mineral: (Ir,Os,Ru) .
initial ratio [radioactivity] . The atomic ratio of two isotopes of an element at the time of crystallization of a mineral containing one or more radioactive elements.
cork cambium . In woody plants, a cambium or lateral meristem in the outer bark that produces cork (phellem) to the outside and phelloderm toward the inside. Syn: phellogen. Cf: periderm [bot]; vascular cambium.
flat-on-flat geometry . The situation where a flat in the hanging-wall template of a fault is juxtaposed against a flat in the footwall template of the fault.
flinkite (flink'-ite). A greenish-brown or green orthorhombic mineral: Mn2+2Mn3+(AsO4)(OH)4 .
permafrost island . A small, shallow, isolated patch of permafrost surrounded by unfrozen ground; occurs on protected north-facing slopes in regions of sporadic permafrost.