Hierarchy of precious substances
In popular culture, sets of precious substances may form hierarchies which express conventional perceived relative value or merit. Precious metals appear prominently in such hierarchies, but as they grow, gems and semi-precious materials may be introduced as part of the system. The sequences can provide interesting examples of the arbitrariness of semiotic signs.
Traditional manifestations
Jubilees have a hierarchy of years: silver (25), golden (50) followed by diamond (60), platinum (70 or 75) and titanium (100).
Wedding anniversaries extend the jubilee hierarchy with various sequences of substances filling in many of the gaps between the major milestones: bronze (8 years) – silver (25 years) – pearl (30) – ruby (40) – gold (50) – diamond (60) – diamond & gold (75).
Ancient Greek mythic-cultural cosmology depicted a decline from a golden age to a silver age followed by an Iron Age. This is even more intense in the Indian Vedic system, where the four ages: Gold, Silver, Bronze, Iron, come with defining characteristics. We are currently in an Iron Age, which will eventually give way to a returning Golden Age.
Modern adaptations
The measurement of sales of popular music starts high relative to the wedding anniversary scale, concentrating on gold and platinum (see gold album). Likewise, credit card companies usually have a "gold card" and a "platinum card" (many formerly had a "silver card" then followed by a "gold card", but due to similarity in appearance between silver and platinum these were often discontinued with the rise in popularity of platinum as a precious metal); Standard Chartered Bank has introduced a "titanium card" as a grade higher than platinum.
Sports events have a well-established convention (introduced into the Olympic tradition at the 1904 Summer Olympics), of a hierarchy of medals: bronze medal - silver medal - gold medal. This presumably echoes conventional coinage systems, in which cheap bronze or copper denominations could aggregate to intermediate silver coins, then to gold money. The archetypal British designations (penny, shilling and pound) parallel and reflect this hierarchy.
Events-sponsorship in sport or in the arts may involve (for example) silver, gold and/or platinum sponsors.