| Gugiaite | |
|---|---|
 | |
| General | |
| Category | Sorosilicate |
| Formula (repeating unit) | Ca2[BeSi2O7] |
| IMA symbol | Gug[1] |
| Strunz classification | 9.BB.10 |
| Dana classification | 55.04.02.06 |
| Crystal system | Tetragonal |
| Crystal class | Scalenohedral (42m) H-M symbol: (4 2m) |
| Space group | P421m |
| Unit cell | a = 7.43, c = 5.024 [Å]; Z = 2 |
| Identification | |
| Color | Colorless |
| Cleavage | Perfect on {010}, distinct {001}, indistinct on {110} |
| Fracture | Uneven – Flat surfaces (not cleavage) fractured in an uneven pattern |
| Mohs scale hardness | 5 |
| Luster | Vitreous, glassy |
| Streak | White |
| Diaphaneity | Transparent |
| Density | 3.03 |
| Optical properties | uniaxial (+) |
| Refractive index | nω = 1.664 nε = 1.672 |
| Birefringence | δ = 0.008 |
| Other characteristics | strongly piezoelectric |
| References | [2][3][4] |
Gugiaite is a melilite mineral, named for the Chinese village of Gugia where it was first discovered. Its chemical formula is Ca2BeSi2O7. It occurs mostly in skarns with melanite adjacent to an alkali syenite and has no economic value. Its crystals are small tetragonal tablets with vitreous luster and perfect cleavage. It is colorless and transparent with a density of three. The mineral belongs to space group P421m and is strongly piezoelectric.
Shortly after the discovery of gugiaite, it was noted that a new name was unnecessary as it could have been considered an end member of meliphanite, (Ca,Na)2Be(Si,Al)2(O,F)2 differing mainly in containing much less sodium and fluorine.[5] Recent data have confirmed that gugiaite differs from meliphanite optically and structurally.[6] Gugiaite is a melilite and is distinctly different from other beryllium minerals such as meliphanite and leucophanite.[6] Gugiaite is named for its locality near the village of Gugia, China.[7] Incongruent information exists regarding Gugia; consequently the actual location of this village within China is unclear (de Fourestier 2005). Gujia is most often referenced as being in either Jiangsu Province or Liaoning Province.[8][9]
- ^ Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
- ^ Handbook of Mineralogy
- ^ "Gugiaite". Retrieved 2024-04-11.
- ^ Webmineral data
- ^ M. Fleischer (1963). "New Mineral Names: Gugiaite". American Mineralogist. 48: 211–212.
- ^ a b J. Grice; F. Hawthorne (2002). "New data on Meliphanite, Ca4(Na,Ca)4Be4AlSi7O24(F,O)4". The Canadian Mineralogist. 40 (3): 971–980. Bibcode:2002CaMin..40..971G. doi:10.2113/gscanmin.40.3.971.
- ^ Chi-Jui Peng; Tsao Rung-Lung; Chou Zu-Rin (1962). "Gugiaite, Ca2BeSi2O7" (PDF). Scientia Sinica. 11 (7): 977–988.
- ^ Zhuming Yang; Michel Fleck; F. Pertlik; E. Tillmanns; K.J. Tao (April 2001). "The crystal structure of natural gugiaite, Ca2BeSi2O7". Neues Jahrbuch für Mineralogie - Monatshefte.
- ^ Joseph A. Mandarino; Jeffrey de Fourestier (March 2005). "Mineral species first found in the People's Republic of China". Rocks & Minerals. 80 (2): 114–117. Bibcode:2005RoMin..80..114M. doi:10.3200/RMIN.80.2.114-117.