The ten records your taste is founded on. The one thing on your profile you claim rather than the app working it out.
A cornerstone is a record your taste is built on. The one that sent you off looking for more like it.
It is not the same as a favourite. Your ranking already says what you think is best, and says it better than a list of ten could.
Something you heard at fourteen and went hunting after is a cornerstone even if you have not played it in ten years. It is about where your looking started, not what you would rate highest today.
The cap is the point. A taste with fifty starting points has none.
Once you have ten and want an eleventh, the app says so and you drop one.
A cornerstone carries a diamond wherever that record appears. On your map it is drawn larger, with an outline. In the worked out ranking it leads its star tier. On your profile the ten sit as a row of sleeves near the top.
It is the only thing on your profile you claim yourself. Everything else the app draws is read off your log.