Batu ahmar
Batu ahmar (juga dieja carnelian[1]) ialah mineral merah keperangan yang biasa digunakan sebagai batu permata separa berharga. Serupa dengan carnelian ialah sard, yang biasanya lebih keras dan lebih gelap (perbezaannya tidak ditakrifkan secara tegar, dan kedua-dua nama itu sering digunakan secara bergantian). Kedua-dua carnelian dan sard adalah jenis kalsedon mineral silika yang diwarnai oleh kekotoran oksida besi. Warnanya boleh berbeza-beza, dari oren pucat hingga warna hampir hitam pekat. Kawasan penting termasuk Yanacodo, Peru dan Ratnapura, Sri Lanka . [2] Ia telah ditemui di Indonesia, Brazil, India, Rusia ( Siberia ), dan Jerman .[perlu rujukan]
| Carnelian | |
|---|---|
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|
| Maklumat am | |
| Kategori | Kepelbagaian kalsedon |
| Formula kimia | Silika (silikon dioksida, SiO2) |
| Pengecaman | |
| Berat molekul | 60 g/mol |
| Warna | Red, orange, reddish |
| Sistem hablur | Trigonal |
| Pembelahan | Absent |
| Fraktur | Uneven, splintery, conchoidal |
| Kekerasan skala Mohs | 6.5 – 7.0 |
| Kilau | Waxy to resinous |
| Indeks biasan | 1.535 to 1.539 |
| Sifat-sifat optik | Uniaxial + |
| Dwibiasan | 0.003 to 0.009 |
| Pleokroisme | None |
| Guris | White |
| Graviti tentu | 2.58 - 2.64 |
| Diafaneiti | Lutsinar kepada legap |
Rujukan
sunting- ^ Websters New World College Dictionary. Fourth Edition. 2001. Editor in chief Michael Agnes.
- ^ Carnelian on Gemdat.org
Bacaan lanjut
sunting- Allchin, B. 1979. "The agate and carnelian industry of Western India and Pakistan". – In: South Asian Archaeology 1975. E. J. Brill, Leiden, 91–105.
- Beck, H. C. 1933. "Etched carnelian beads". – The Antiquaries Journal, 13, 4, 384–398.
- Bellina, B. 2003. "Beads, social change and interaction between India and South-east Asia". – Antiquity, 77, 296, 285–297.
- Brunet, O. 2009. "Bronze and Iron Age carnelian bead production in the UAE and Armenia: new perspectives". – Proceedings of the Seminar for Arabian Studies, 39, 57–68.
- Carter, A. K., L. Dussubieux. 2016. "Geologic provenience analysis of agate and carnelian beads using laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS): A case study from Iron Age Cambodia and Thailand". – J. Archeol. Sci.: Reports, 6, 321–331.
- Cornaline de l'Inde. Des pratiques techniques de Cambay aux techno-systèmes de l'Indus (Ed. J.-C. Roux). 2000. Éditions de la Maison des sciences de l'homme, Paris, 558 pp.
- Glover, I. 2001. "Cornaline de l'Inde. Des pratiques techniques de Cambay aux techno-systèmes de l'Indus (sous la direction de V. Roux). – Bulletin de l'École française d'Extrême-Orient, 88, 376–381.
- Inizan, M.-L. 1999. "La cornaline de l’Indus à la Mésopotamie, production et circulation: la voie du Golfe au IIIe millénaire". – In: Cornaline et pierres précieuses. De Sumer à l'Islam (Ed. by F. Tallon), Musée du Louvre, Paris, 127–140.
- Insoll, T., D. A. Polya, K. Bhan, D. Irving, K. Jarvis. 2004. "Towards an understanding of the carnelian bead trade from Western India to sub-Saharan Africa: the application of UV-LA-ICP-MS to carnelian from Gujarat, India, and West Africa". – J. Archaeol. Sci., 31, 8, 1161–1173.
- Kostov, R. I.; Pelevina, O. (2008). "Complex faceted and other carnelian beads from the Varna Chalcolithic necropolis: archaeogemmological analysis". Proceedings of the International Conference "Geology and Archaeomineralogy". Sofia, 29–30 October 2008. Sofia: Publishing House "St. Ivan Rilski": 67–72.
- Mackay, E. 1933. "Decorated carnelian beads". – Man, 33, Sept., 143–146.
- Theunissen, R. 2007. "The agate and carnelian ornaments". – In: The Excavations of Noen U-Loke and Non Muang Kao (Eds. C. Higham, A. Kijngam, S. Talbot). The Thai Fine Arts Department, Bangkok, 359–377.