megacrystn.
/ˈmɛɡəkrɪst/, U.S. /ˈmɛɡəˌkrɪst/ Geology.
In an igneous or metamorphic rock: a crystal that is significantly larger than those in the surrounding groundmass or matrix.
ΚΠ
1958 J. W. Clarke Bedrock Geol. Danbury Quadrangle (State Geol. & Nat. Hist. Surv. of Connecticut, Quadrangle Rep. No. 7) 12 The Danbury region augen granite is a porphyritic gneissic granite... It is a distinctive rock characterized by large microcline megacrysts.
1988 Nature 27 Oct. 788/2 Crystallization of kimberlitic or lamproitic melts at depth has been suggested as the origin of megacrysts.
1998 Canad. Mineralogist 36 1 Radiating sprays of schorl and flaring megacrysts of K-feldspar (intermediate microcline) point inward, indicating progressive crystallization toward the core.
This is a new entry (OED Third Edition, June 2001; most recently modified version published online March 2022).
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n.1958- to set on cinque and sice
- to set on delay
- to set on edge
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- to set on his feet
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- to set on his legs
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- to set on one's feet, legs
- to set on one's foot
- to set on one's heart
- to set on or upon the square
- to set on sale
- to set on seven
- to set on six and seven
- to set on the panel
- to set on the sea, water, afloat