[lam-pruh-fahyuh
r] 
| any dark intrusive rock in which dark minerals occur both as phenocrysts and as groundmass. |
[lam-pruh-fir-ik] , adjective | lam·pro·phyre (lām'prə-fīr') n. Any of several intermediate igneous rocks constituting feldspar and ferromagnesium minerals that occur as dikes and minor intrusions. [German Lamprophyr : Greek lampros, clear (from lampein, to shine) + French porphyre, porphyry (from Old French porfire; see porphyry).] |
| lamprophyre (lām'prə-fīr') Pronunciation Key
A dark igneous rock, having a porphyritic texture in which both the phenocrysts (larger crystals) and the matrix consist primarily of pyroxene, hornblende, and biotite. |
lamprophyre
any of a group of dark gray to black intrusive igneous rocks that generally occur as dikes (tabular bodies inserted in fissures). Such rocks are characterized by a porphyritic texture in which large crystals (phenocrysts) of dark, iron-magnesium (mafic) minerals are enclosed in a fine-grained to dense matrix (groundmass). The abundance, large size, well-formed crystal outline, and brilliantly reflecting cleavage faces of the mafic phenocrysts give the rock a striking appearance. Mafic minerals, including biotite, hornblende, augite, or olivine, not only constitute virtually all of the phenocrysts but occur in the groundmass as well, together with much potash feldspar, plagioclase, or feldspathoid.
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