Supply and demand
It does not tarnish, and remains shiny; it is difficult to obtain, and therefore valuable; and it is pretty.
Trade secrets require some amount of effort by a business to protect them legally. Copyrights are easy to obtain legally, but difficult to enforce in practice. Patents are somewhat difficult and often expensive to obtain and enforce. Trademarks are easy to obtain but not always easy to enforce.
Yes, education is extremely expensive for children in Ghana and therefore it is very difficult for parents to send their children to school.
Diamond, sapphire,emrald, ruby they all are expensive
Extremely difficult; see the link below.
Lutetium This element is very expensive to obtain in useful quantities and therefore it has very few commercial uses. However, stable lutetium can be used as catalysts in petroleum cracking in refineries and can also be used in alkylation, hydrogenation, and polymerization applications.
Non military semi automatic FNH P90's can go from $1,600 and up fully automatic military versions are far more expensive and are difficult to obtain as a civilian.
reall hard
it is pretty had
Copper melts at a lower temperature than iron. Therefore, in order to remove it from the ore in which it is found, and in order to work it, a hotter fire is needed to for iron than for copper. Making a fire hot enough to extract and work iron is more difficult, so iron tools were more difficult to obtain than copper tools.
This usage would require a synchronization license, which can be difficult and expensive to obtain. Many publishers have online request forms.
Because it is strong, because it is "massive" (which is to say that it does not have planes of weakness that it tends to split or crack along), because it is durable, and because it is non-porous and therefore impervious to seepage. On the other hand it is hard, and therefore difficult to work, and therefore expensive.