For some examples of early medieval gold polychrome jewellery featuring Indian/Sri Lankan garnets, demonstrating the widespread use of this style in the 5th—7thC, see this thread, https://twitter.com/caitlinrgreen/status/894150359169585152 …, and https://www.researchgate.net/profile/Thomas_Calligaro2/publication/280954735_Contribution_a_l%27etude_des_grenats_merovingiens_Basilique_de_Saint-Denis_et_autres_collections_du_musee_d%27Archeologie_nationale_diverses_collections_publiques_et_objets_de_fouilles_recentes_Nouvelles_/links/5630707e08ae432a022c3fda/Contribution-a-letude-des-grenats-merovingiens-Basilique-de-Saint-Denis-et-autres-collections-du-musee-dArcheologie-nationale-diverses-collections-publiques-et-objets-de-fouilles-recentes-Nouvelles-a.pdf …