Characterization of Natural Precious Opal Using Modern Spectroscopic Techniques in Ethiopia: The Case from Delanta, South Wollo

Table 3

Comparison of some optical and structural properties of Delata district opals with other countries’ opals [21].

	Sample	Location	Color	Classification	Opal type
Ethiopia	Ds-1	Workwasha	Yellow dominant blue reddish	Precious	CT
	Ds-2	Alehuat	Brownish dominant reddish green	Precious	CT
	Ds-3	Nech-gedel	Blue reddish	Precious	CT
	Ds-4	Abobetach	Brownish dominant green	Precious	CT
	Ds-5	Chegen	Yellowish green	Precious	CT
	Ds-6	Gelbate	Yellow dominant blue reddish	Precious	CT
Australia	AU047	Andamooka	Yellow	Common/precious	A/CT
	AU008	Andamooka	White	Common	CT
	AU110	Andamooka	Uncolored	Common	A
	AUM8	Andamooka	Yellow	Common/precious	CT
	AU120	Coober Pedy	Turquoise	Common	A
USA	U1240	Virgin Valley	Black	Precious	CT
	U01	Humboldt Valley	Yellow	Common	CT
Slovakia	SL01	Dubník	White	Precious	A
	SL03	Herlany	Opaque red	Common	CT
	SL1243	Košice	Uncolored	Common	CT
Madagascar	MA1211	Unknown	Green	Common	CT
Mexico	MX1403	Unknown	Milky yellow	Common	C
	MX1233	Hidalgo	Uncolored	Common	CT