What Unicode characters represent "time"?

What Unicode character symbol(s) express duration (such as a clock, hourglass, or other timepiece)?

For example "★3⅔" instead of "3 hours and forty minutes", where ★ is a time symbol.

The following code points exist related to clocks, watches, and other devices to indicate time:

⌚  U+0231A  WATCH
⌛  U+0231B  HOURGLASS
⏰  U+023F0  ALARM CLOCK
⏱  U+023F1  STOPWATCH
⏲  U+023F2  TIMER CLOCK
⏳  U+023F3  HOURGLASS WITH FLOWING SAND
⧖  U+029D6  WHITE HOURGLASS
⧗  U+029D7  BLACK HOURGLASS
📅  U+1F4C5  CALENDAR
📆  U+1F4C6  TEAR-OFF CALENDAR
🕐  U+1F550  CLOCK FACE ONE OCLOCK
🕜  U+1F55C  CLOCK FACE ONE-THIRTY
🕑  U+1F551  CLOCK FACE TWO OCLOCK
🕝  U+1F55D  CLOCK FACE TWO-THIRTY
🕒  U+1F552  CLOCK FACE THREE OCLOCK
🕞  U+1F55E  CLOCK FACE THREE-THIRTY
🕓  U+1F553  CLOCK FACE FOUR OCLOCK
🕟  U+1F55F  CLOCK FACE FOUR-THIRTY
🕔  U+1F554  CLOCK FACE FIVE OCLOCK
🕠  U+1F560  CLOCK FACE FIVE-THIRTY
🕕  U+1F555  CLOCK FACE SIX OCLOCK
🕡  U+1F561  CLOCK FACE SIX-THIRTY
🕖  U+1F556  CLOCK FACE SEVEN OCLOCK
🕢  U+1F562  CLOCK FACE SEVEN-THIRTY
🕗  U+1F557  CLOCK FACE EIGHT OCLOCK
🕣  U+1F563  CLOCK FACE EIGHT-THIRTY
🕘  U+1F558  CLOCK FACE NINE OCLOCK
🕤  U+1F564  CLOCK FACE NINE-THIRTY
🕙  U+1F559  CLOCK FACE TEN OCLOCK
🕥  U+1F565  CLOCK FACE TEN-THIRTY
🕚  U+1F55A  CLOCK FACE ELEVEN OCLOCK
🕦  U+1F566  CLOCK FACE ELEVEN-THIRTY
🕛  U+1F55B  CLOCK FACE TWELVE OCLOCK
🕧  U+1F567  CLOCK FACE TWELVE-THIRTY
🕰  U+1F570  MANTELPIECE CLOCK
🗓  U+1F5D3  SPIRAL CALENDAR PAD

You can copy and paste the characters from this page into most editors.

At unicode-table.com you might find more useful code points.

Chars:

◴◵◶◷

Unicode number:

U+25F4 - U+25F7

HTML code:

◴ - ◷

are working for me

A collection of clock faces has been proposed as part of the new Emoji set, in the range from U+1F550 to U+1F55B. Browser/font support is pretty much completely absent, sadly.

Here's one of the clock faces:

Also proposed is an alarm clock symbol at U+23F0:

More about the Emoji set here.

Maybe ⌛ U+231B HOURGLASS

Check that similar question: What Unicode character do you use in your website? (instead of image icons)