- journal_title：The Canadian Mineralogist
- Contributor：George E. Harlow ; A. Reg Murphy ; David J. Hozjan ; Christy N. de Mille ; Alfred A. Levinson
- Publisher：Mineralogical Association of Canada
- Date：2006-
- Format：text/html
- Language：en
- Identifier：10.2113/gscanmin.44.2.305
- journal_abbrev：Can Mineral
- issn：0008-4476
- volume：44
- issue：2
- firstpage：305
- section：Articles
Excavation of ornamental and gem materials from workshop sites on the island of Antigua, West Indies, also uncovered jade celts (axe forms) and fragments thereof. All are jadeite jades (jadeitite), like jades from Mesoamerica. The Antigua sites date to the Saladoid period (ca. 250–500 AD), roughly equivalent to early Classic period for Mesoamerican cultures, and reveal “jades” used in a context (i.e., decorative celt) well developed by Mesoamericans some 3100 km to the West. Ten of these jade artifacts were examined by a combination of mineralogical and petrographic techniques to determine their mineral constituents, mineral compositions and petrographic textures, in order to place them in a context of possible sources among worldwide sources of jadeite jade. The common assemblage for six artifacts studied as polished sections include jadeite, omphacite, albite, a white-tan mica, quartz, zoisite or clinozoisite and titanite, with the exception of one artifact lacking albite and quartz, and one lacking mica. Allanite was found in the cores of zoisite in two jades, and glaucophane and lawsonite, each, were observed in single samples of jade. The other four jades, which could not be studied as well, seem to contain comparable assemblages. Conspicuous among the Antigua jades is the textural setting of quartz, a phase absent from jadeitite from most sources worldwide. Quartz exists either as a secondary matrix phase around corroded grains of jadeite (tiny omphacite grains in quartz decorate the boundaries of the jadeite) or as inclusions in jadeite associated with smaller regions of omphacite. In comparison with jadeitite from ~12 described occurrences worldwide, only jadeitite from south of the Motagua fault zone (MFZ) in Guatemala regularly contain the appropriate assemblage, including white mica and quartz. Moreover, glaucophane and lawsonite have also been observed in jadeitite from this source, and textures are also highly similar. However, differences include absence of zoisite or clinozoisite and paragonite, plus some divergences in pyroxene compositions in Guatemalan jadeitite from south of MFZ compared to the Antigua jades. Although Guatemala is a reasonable source for the Antigua jades, as yet unknown sources in a similar geological terrane (serpentinite–matrix mélange) on Cuba, Hispaniola or Jamaica cannot be ruled out.