throughout history value have differed. For example today oil is valuable while centuries ago it was not. I believe gold and silver has always been valuable.
interested in finding out what were the top 5 to 10 most valuable commodities besides gold and silver. Somewhere I read salt used to be valuable at one time.
also where can i find additional research on which commodities were valuable at different periods in history.
Gold and silver have been valuable commodities throughout history because they have always been relatively rare and hard to obtain. For the same reason, precious stones have also generally been regarded as valuable.
Many other items have been valuable at times based on scarcity and demand. You mention salt, which was in many parts of the ancient world quite valuable. During much of the middle ages, spices from the far east, including nutmeg, cinnamon, cloves, pepper and tea, were quite valuable in Europe, as was silk. The difficulty in transporting these items, which were relatively less expensive in Asia, made their scarcity in Europe of great value. In the summer, even ice became a valuable commodity, since it had to be carried quickly from mountain tops back to the wealthy consumer who wanted to consume it.
Until the early 20th Century, aluminum was extremely valuable, more valuable than gold. It was extremely hard to extract, making processed aluminum very rare. Once a better processing method was developed in the early 20th century, the price plummeted. Other metals have held some value, particularly copper, which has been used for coins for thousands of years along with gold and silver.
In the early years of America, furs became a valuable commodity in Europe. The fur trade built a large number of financial empires. In this same era, sugar was also extremely valuable. It became less so as large sugar plantations in the Caribbean increased supply though.
Sometimes items become highly valuable for a short period of time due to fads. For example, in the early 1600's in Europe, tulip prices went crazy, some bulbs selling for thousands of dollars. Once the fad passed, however, the prices once again crashed.
Today modern transport and production methods mean that most things that are capable of being produced can be supplied in amounts that keep prices down. Even oil is relatively inexpensive, though its value is in the fact that billions of gallons are used every day. On a per gallon basis though, oil is far less expensive than soda or even bottled water.
More valuable commodities today are those that are illegal, and thus cannot be transported and sold through normal commercial enterprises. Drugs like heroin or cocaine are more valuable than gold today on a per pound basis, specifically because they are hard to produce and transport, yet desired by many paying customers.