From Longman Dictionary of Contemporary Englishagateag‧ate /ˈæɡət/ noun [countable, uncountable] 
DCJa hard stone with bands of different colours, used in jewellery
DCJa hard stone with bands of different colours, used in jewelleryExamples from the Corpus
agate• Most of the seals were nevertheless made of bone, ivory, steatite, banded agate, or orange carnelian.• Sometimes, they were moss green, tantalising as moss agate.• Beneath her flat furry belly the big shallow stones had the marble veining of agate.Origin agate (1500-1600) French Latin achates, from Greek 