The purple heart has more than one owner
Ask three people what 💜 means and you can get three answers. For BTS ARMY it is a loyalty badge, and the "borahae" greeting is often written as a single purple heart. Others use it for the United States military Purple Heart medal, especially on Veterans Day posts about wounded service members. Plenty of senders mean neither and simply want a heart that feels softer than ❤️ and less romantic. Because of that overlap, 💜 is safe almost anywhere, but if you need a message read one way only, add a word of context.
Purple by design, not by name
Only three emoji in our list carry the word purple in their official names: 💜, 🟣 and 🟪. Everything else on this page is purple because artists chose it. 😈 smiling face with horns and 👿 imp are violet on Apple, Google and most other sets, which is how "purple devil" became a common nickname. 🍆 is dark purple on nearly every platform, a large part of why it took on its well known innuendo. 🍇 grapes and 🪻 hyacinth are purple because the real things are. A few, like 👾 alien monster, change shade between vendors, so check before building a strict colour theme around them.
When the circles and squares arrived
🔴 and 🔵 have been emoji since 2010, but a full rainbow of plain shapes only landed in Emoji 12.0 in 2019, when 🟣 joined new orange, yellow, green and brown circles and a set of seven coloured squares including 🟪 appeared. The swatches are popular in colour coded lists, poll options and team labels, where 🟣 can stand for one group without carrying a heart's emotional weight. On devices older than that release they appear as empty boxes, which is rare on phones now but still turns up on old office computers.