Assertion: blue enamel | /r/HasProperty | obtained for example
Facets:
value: from the black oxide of copper
type: OTHER
Source sentences:
text: For example, turquoise-blue enamel can be obtained from the black oxide of copper by using a comparatively high proportion of carbonate of soda; in the same way, a yellowish-green enamel can be obtained from the same black oxide by increasing the proportionate amount of red lead.