Subhedral

Monazite occurs as anhedral to subhedral masses associated with phyllosilicate-rich domains in massive sulfides. Masses display simple concentric zoning, a primary core, and commonly show fracturing and healing involving later generations of monazite growth that are likely a product of metamorphism (Fig. 2a). 

This investigation relied on petrographic analysis of polished sections using reflected light and the scanning electron microscopy (SEM) and electron microprobe (EPMA) analyses to identify minerals and to document the distribution of gold. The mineralized zone is coincident with a distinct bleached alteration zone that contains fine- to coarse-grained, subhedral arsenopyrite and pyrite in quartz-carbonate veins. 

A record of morphology classes for each pyrite occurrence was kept during petrographic analyses. Monocrystalline pyrite includes euhedral and subhedral pyrite crystals. This morphology class is always more prevalent than framboidal pyrite except at the top of core 1 and the bottom of core 3. 

Figure 5. SEM photomicrograph of Predynastic (ca. 5500 B.P.) bone found buried in the soil at Tel-Roba. Apatite groundmass of bone (A) is covered with kaolinite clay (K) and coarse subhedral grains of hematite.

Kakangari matrix contains mostly euhedral to subhedral crystals with grain sizes of 200 nm to... 

Fig. 7. Garnet zoning profiles from Domain V. (a) A subhedral garnet in 462536 with an inclusion-rich, Mn-rich core and a rim with fewer inclusions, (b) Deformed and altered garnet in 466466 showing Garnet-1 and Garnet-2 growth (garnet shown in crossed polars).

Siderite is most abundant (up to 14%) in finegrained sandstones rich in mica and clay pseudomatrix. It occurs as small subhedral or flattened rhombs (<3-15 pm) (Fig. lOF) that replaced the detrital clays, and expanded as well as replaced the mica flakes (Fig. 13A). In coarser-grained sand-... 

Late ferroan dolomite forms large cloudy crystals riddled with inclusions (Fig. 15A), patches of sparry dolomite (Fig. 15B) and large individual euhedral to subhedral rhombs (Fig. 15D) up to... 

Replacement dolomite forms euhedral to subhedral rhombs up to 85 pm in diameter in the clay matrix of sandstones and in early ferroan calcite cement. 

Photograph 3-5 Large, round, slightly ragged belite blue subhedral to anhedral alite and matrix of aluminate (CjA, arrow) and ferrite. Superimposed nital over KOH produces increased clarity in matrix phase definition. (S A6615)... 

Photograph 7-15 Euhedral to subhedral, zoned, yellowish tan alite dark, round belite with typical multidirectional lamellae and a well-differentiated matrix of aluminate (C3A) and ferrite (C AF). Small belite inclusions in alite. Epoxy-filled pore at bottom of photo. Coal-fired kiln, wet-process, 1000 tons/day, 38 MPa coarse seashell feed (30% greater than 75 pm). (S A6635)... 

Photograph 7-21 Blue, subhedral alite crystals with very narrow belite fringe (almost the only belite in the clinker) and matrix of gray aluminate and dull ferrite. Average alite size is approximately 26 pm. Coal-fired, dry-process kiln, 550 tons/day. (S A6641)... 

Subhedral, pseudohexagonal, lath shaped alite and belite clusters (subround), some hexagonal belite Coal ash absorption (Rao and others, 1993)... 

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