Opal is a hydrated amorphous form of silica (SiO2·nH2O) which its water content may range from 3 to 21% by weight, most of the opal from Wollo, Ethiopia, is hydrophane. The term hydrophane comes from the Greek words meaning “water-loving” and describes their ability to absorb water and change from opaque or semi-translucent to translucent […]
Hydrophane Ethiopian Opal Read More »
A bench jeweller submitted a black stone (Material A) which he claim bought from South Africa, and believed to be a “Black Diamond”. The bench jeweller tested it with his own standard thermal conductivity diamond tester, and the result indicated that the Material A is a Diamond. The bench jeweller submitted the Material A, and
A 73 carat rough stone (Stone A) submitted for identification. Stone A labeled as “Berlian” (Diamond in Malay language) by the customer, and were told mined from East Malaysia, Borneo Island Sabah based on the information provided by the customer’s supplier. Customer has strong believe that the submitted stone is a diamond base on the two
Jadeite jade’s color is the key important factor in evaluating its value. For decades, artist, sculptor, carver spend countless effort in study, planning, carve and re-carving their jade piece in order to bring out the best nature of their colour. However, with the current technology and trade demand, all the colour of a jadeite jade may
Residue of Polishing Powder? Read More »
