Gyrolite

Gyrolite, NaCa₁₆(Si₂₃Al)O₆₀(OH)₈·14H₂O,[2] is a rare silicate mineral (basic sodium calcium silicate hydrate: N-C-S-H, in cement chemist notation) belonging to the class of phyllosilicates. Gyrolite is also often associated with zeolites. It is most commonly found as spherical or radial formations in hydrothermally altered basalt and basaltic tuffs.[2] These formations can be glassy, dull or fibrous in appearance.[4]

Gyrolite
Gyrolite
General
Category	Phyllosilicate
Formula (repeating unit)	NaCa16(Si23Al)O60(OH)8·14H2O
Strunz classification	9.EE.30
Dana classification	73.2.2c.1
Crystal system	Triclinic
Crystal class	Pinacoidal (1) (same H-M symbol)
Space group	P1
Unit cell	a = 9.74, b = 9.74 c = 22.4 [Å]; α = 95.71° β = 91.51°, γ = 120.01°; Z = 4
Identification
Color	White, colorless, green, yellow or brown
Crystal habit	Compact, lamellar, platy
Twinning	Lamellar
Cleavage	Perfect on {001}
Tenacity	Brittle
Mohs scale hardness	​2 ^1⁄2
Luster	Vitreous, pearly
Diaphaneity	Transparent, translucent, opaque
Density	2.45 - 2.51
Optical properties	Biaxial (-)
Refractive index	nα = 1.535 nβ = 1.548 nγ = 1.549
Birefringence	δ = 0.0140
References	[1][2][3]

Gyrolite is also known as centrallasite, glimmer zeolite or gurolite.[2]

Discovery and natural occurrence

It was first described in 1851 for an occurrence at The Storr on the isle of Skye, Scotland and is named from the ancient Greek word for circle, guros (γῦρος), based on the round form in which it is commonly found.[3]

Minerals associated with gyrolite include apophyllite, okenite and many of the mother zeolites.[4] Gyrolite is found in Scotland, Ireland; Italy, Faroe Islands, Greenland, India, Japan, USA, Canada and various other localities.[1][2]

Spherically shaped crystals of gyrolite: Lonavala Quarry, Lonavale (Lonavala), Pune District (Poonah District), Maharashtra, India.

Occurrence in hardened cement paste and concrete

Gyrolite is also mentioned as a rare calcium silicate hydrate (C-S-H) phase in cement chemistry textbooks [5][6] with a simplified formulation: Ca₈(Si₄O₁₀)₃(OH)₄ · ~6 H₂O, which is consistent with the general formulation given here above, but does not consider the isomorphic substitution of one silicon atom by one aluminum and one sodium atoms in its crystal lattice. Gyrolite may form at higher temperature in oilwell cement muds containing ground granulated blast furnace slags (GGBFS) activated by alkali. It could also form in CEM III cement-based concrete exposed to alkali-silica reaction (ASR) at elevated temperature.

Hydrothermal synthesis

Gyrolite can be synthesized in the laboratory, or industrially, by hydrothermal reaction in the temperature range 150 – 250 °C by reacting CaO and amorphous SiO₂, or quartz, in saturated steam in the presence of CaSO₄ salts or not.[7][8] At temperature lower than 150 °C, the reaction rate is very slow. At temperature above 250 °C, gyrolite recrystallizes into 1.13 nm tobermorite and xonotlite.[7] Gyrolite is also one of the rare phases detected in situ along with pectolite by synchrotron X-rays diffraction in hydrothermal synthesis of cement.[9] Synthetic gyrolite has also a large specific surface and could enter industrial applications as oil absorber.[10] Gyrolite globular rosettes resemble that of shlykovite,[11][12] a new natural crystalline C-S-H mineral characterized in 2010 and also to mountainite and rhodesite, other crystalline ASR products of the same family.[13][14][15][16]

See also

• Apophyllite
• Carbonatite
• Phyllosilicates
• Zeolite

References

1. Gyrolite in the Handbook of Mineralogy
2. "Gyrolite".
3. Dave Barthelmy. "Gyrolite Mineral Data".
4. "Gyrolite (Hydrated Calcium Silicate Hydroxide)". Galleries.com. Retrieved 2016-02-27.
5. Hewlett, Peter (2003). Lea's chemistry of cement and concrete. See chapter 14.2 Oilwell cement, p. 807. Elsevier. ISBN 0-08-053541-0.
6. Taylor, Harry F.W. (1997). Cement chemistry. See gyrolite at pp. 344 and 348. Thomas Telford. ISBN 0-7277-2592-0.
7. Siauciunas, R.; Baltakys, K. (2004). "Formation of gyrolite during hydrothermal synthesis in the mixtures of CaO and amorphous SiO₂ or quartz". Cement and Concrete Research. 34 (11): 2029–2036. doi:10.1016/j.cemconres.2004.03.009. ISSN 0008-8846.
8. Baltakys, K.; Siauciunas, R. (2010). "Influence of gypsum additive on the gyrolite formation process". Cement and Concrete Research. 40 (3): 376–383. doi:10.1016/j.cemconres.2009.11.004. ISSN 0008-8846.
9. Shawa, S.; Henderson, C. M. B.; Clark, S. M. (2001). "Hydrothermal synthesis of cement phases: An in situ synchrotron, energy dispersive diffraction study of reaction kinetics and mechanisms". High Pressure Research. 20 (1–6): 311–324. Bibcode:2001HPR....20..311S. doi:10.1080/08957950108206179. ISSN 0895-7959.
10. "Patent application number: 15/034,912. Inventors: Yuuta Tsumura (Naruto-shi), Kazuki Kamai (Naruto-shi), Yukinori Konishi (Naruto-shi), Kazuhiko Tamagawa (Naruto-shi). Powdered gyrolite-type calcium silicate having high oil absorbency and large particle diameter, and production method therefor". Nov 7, 2014.
11. Zubkova, Natalia V.; Filinchuk, Yaroslav E.; Pekov, Igor V.; Pushcharovsky, Dmitry Yu; Gobechiya, Elena R. (2010-08-01). "Crystal structures of shlykovite and cryptophyllite: comparative crystal chemistry of phyllosilicate minerals of the mountainite family". European Journal of Mineralogy. 22 (4): 547–555. Bibcode:2010EJMin..22..547Z. doi:10.1127/0935-1221/2010/0022-2041. ISSN 0935-1221. Retrieved 2020-04-29.
12. Pekov, I. V.; Zubkova, N. V.; Filinchuk, Ya. E.; Chukanov, N. V.; Zadov, A. E.; Pushcharovsky, D. Yu.; Gobechiya, E. R. (2010-12-01). "Shlykovite KCa[Si₄O₉(OH)] · 3 H₂O and cryptophyllite K₂Ca[Si₄O₁₀] · 5 H₂O, new mineral species from the Khibiny alkaline pluton, Kola Peninsula, Russia". Geology of Ore Deposits. 52 (8): 767–777. Bibcode:2010GeoOD..52..767P. doi:10.1134/S1075701510080088. ISSN 1555-6476.
13. De Ceukelaire, L. (1991-05-01). "The determination of the most common crystalline alkali-silica reaction product". Materials and Structures. 24 (3): 169–171. doi:10.1007/BF02472981. ISSN 1871-6873.
14. Dähn, R.; Arakcheeva, A.; Schaub, Ph.; Pattison, P.; Chapuis, G.; Grolimund, D.; Wieland, E.; Leemann, A. (2016-01-01). "Application of micro X-ray diffraction to investigate the reaction products formed by the alkali–silica reaction in concrete structures". Cement and Concrete Research. 79: 49–56. doi:10.1016/j.cemconres.2015.07.012. ISSN 0008-8846. Retrieved 2020-04-29.
15. Shi, Zhenguo; Leemann, Andreas; Rentsch, Daniel; Lothenbach, Barbara (2020-05-01). "Synthesis of alkali-silica reaction product structurally identical to that formed in field concrete". Materials & Design. 190: 108562. doi:10.1016/j.matdes.2020.108562. ISSN 0264-1275. Retrieved 2020-04-29.
16. Geng, Guoqing; Shi, Zhenguo; Leemann, Andreas; Borca, Camelia; Huthwelker, Thomas; Glazyrin, Konstantin; Pekov, Igor V.; Churakov, Sergey; Lothenbach, Barbara; Dähn, Rainer; Wieland, Erich (2020-03-01). "Atomistic structure of alkali-silica reaction products refined from X-ray diffraction and micro X-ray absorption data". Cement and Concrete Research. 129: 105958. doi:10.1016/j.cemconres.2019.105958. ISSN 0008-8846. Retrieved 2020-04-29.

Further reading

• Anderson Thomas (1851) Description and analysis of gyrolite, a new mineral species. In: The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science, Vol. 1, 111–113. (PDF 239,5 kB)
• Fleischer M. (1959) New mineral names. In: American Mineralogist, Vol. 44, 464–470 (PDF 444 kB; p. 7: Centrallasite = Gyrolite).