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TECHNICAL PAPER

MAJOR XRD PEAKS AND OR INTENSITY AND D-SPACING (26.642, 100, 3.34321), (20.861, 20.9, 4.25478) 21.60-21.75, 2θ, 35.80-35.9, 2θ 21.74-22.00, 2θ, 4.12-4.05, d-spacing 20.6-20.7, 2θ, 21.8-23.2, 2θ, 35.3, 2θ (humped) - - (20.552, 100, 4.31806), (21.702, 71.4, 4.09175) (21.947, 100, 4.04659), (36.056, 13.9, 2.48900) (27.915,100, 3.19357), (22.055, 71.1, 4.02715) (26.912, 100, 3.31034), (27.578, 81.4, 3.23179) (27.070, 100, 3.29127), (27.511, 96.3, 3.23391) (27.891, 100, 3.19

OPTICAL PROPERTIES INTERFERENCES IN THIN SECTION Max. interference gray (may interstitial or vermicular) Max. interference dark gray – Cryptocrystalline Max. interference dark gray - Cryptocrystalline Max. interference dark gray - Cryptocrystalline Max. interference dark gray – Cryptocrystalline (Bladed) Max. interference dark gray - Intergrown tiny quartz Max. interference dark gray – wedge shaped twins Max. interference dark gray No colour to grey interferences- zebra str

Table 4: Identification and characterization of common minerals in aggregates [1, 7-11, 15-18]

INDICATIVE MEAN RI (BIREFRINGENCE) 1.54 (Very Low) 1.42 (None) 1.42 (None) 1.42 (None) 1.54 (Very Low) 1.75 (Very Low) 1.48 (Very Low) 1.48 (Very Low) 1.52 (Low) 1.52 (Low) 1.52 (Low 1.59 (Very low) 1.54 (Low) 1.57 (Very high) 1.60 (Very high) 1.56 (Moderate) 1.55 (Very high) 1.60(Very high) 1.70 (Very high) 1.66 (Low) 1.71 (Moderate) 1.65 (Low) 1.68 (High) 1.67 (Low) 1.65(High) 1.88 (High) 1.66(Moderate)

CLEAVAGE / FRACTURE No cleavage / conchoidal Compact and vitreous / conchoidal or granular Partly crystallized /conchoidal or granular Friable and dispersed / conchoidal or granular No cleavage/conchoidal or granular Not visible/splintery- (sub) conchoidal No cleavage/conchoidal No cleavage/conchoidal Perfect to poor/uneven Perfect to poor (90° cleavage angle)/uneven Perfect to poor (90° cleavage angle)/uneven Perfect to poor/uneven Perfect to poor/concho

CRYSTAL HABIT Hexagonal- Prismatic or massive Well-ordered α-cristobalite Disordered α-cristobalite and α-tridymite Highly disordered and amorphous Parallelly grown or fibrous or radiating Wedge shaped crystals Cubic or octahedral Subhedral or twinned. Rarely euhedral or Prismatic, stubby or elongated to Prismatic, stubby or elongated to Cleavable masses, tabular or bladed or Euhedral or anhedral / massive to Hexagonal prisms, rhombohedra with basal faces Fibr

MINERALS Quartz Opal: Opal C [18] Opal CT [18, 19] Opal A [19] Chalcedony needles Flint Fibrous Tridymite Cristobalite Albite prismatic Orthoclase Microcline flattened Anorthite Plagioclase flattened prismatic granular Calcite Aragonite Vaterite Dolomite Magnesite Siderite earthy Hornblende Augite Enstatite Diopside Jadeite Forsterite Fayalite Monticellite granular granular

10 THE INDIAN CONCRETE JOURNAL | AUGUST 2022