During the early medieval period, what classes of materials were typically reserved for royalty and the extremely affluent?

Gold, silver, crystal, or ivory

In the earlier historical periods, including the early medieval era, the materials used for buttons directly reflected the wearer's economic standing. The most common, everyday buttons were fashioned from locally sourced, readily available natural materials like wood, horn, or shell. In sharp contrast, royalty and the wealthiest segments of society commissioned buttons made from precious metals such as gold and silver, or carved materials like ivory, often further enhancing them with the addition of encrusted gemstones to signify immense affluence.