We analyzed 99 of the tweets by @すらしょー（ヒスイのすがた？） and here's what we found.
Note Timezone shown is UTC+0. Current UTC time is 09:18:37 +0000. The world clock can help you compare different timezones. If the tweets are spread evenly across the full 24 hour span, chances are that it's been set up to tweet automatically.