Ruby / ルビー
First appearance Chapter 59
Status Inactive prior to beginning of the story
Race Gem
Age Unknown
Hardness 9
Family The other Gems
Occupation Unknown
Teammate Yellow Diamond (former)
Voice Actors
Ruby (ルビー, Rubī) is one of the Gems who presumably did patrol duty. They are currently a captive on the Moon.


Ruby has only made appearances in flashbacks of other characters. Based on their name, they are assumed to have a red color feature. Their hair has wavy features, with two frontal locks on either side of their head. Bangs sweep over the right eye, and a ponytail accents the same side. They wear the typical school uniform, with thigh-high socks to top it all off. Their eyes carry the tsurime trait, eyes with sharp corners.


Ruby has only been seen in a cameo without any dialogue or actions so there is currently no information on their personality other than their appearance. Ruby has tsurime eyes, eyes with sharp corners which are generally an indication of having a tough personality rather than a soft one so presumably this applies to Ruby.


Ruby was taken by the the Lunarians prior to the beginning of the story. They were partnered with Yellow Diamond at the time. Late in the series, Yellow Diamond reminisces about all the Gems that were lost while partnered with them, including Ruby, Pink Topaz, Green Diamond, and Sapphire. Yellow Diamond mentions they wish to talk with them again, even if they can't return from the Moon. Yellow expresses guilt at not being able to prevent their capture and has wanted to apologize to them.


Like how other Gems treat each other, it can be assumed that Ruby has nice relationship with their other siblings and also like and trust Kongo-sensei.

Gem Info

  • Mineral: Oxide (Corundum)
  • Chemistry: Al2O3:Cr
  • Color: Shades of red

ruby is a pink to blood-red colored gemstone, a variety of the mineral corundum (aluminium oxide), which includes sapphire and padparadscha. The red color is caused mainly by the presence of the element chromium. Its name comes from ruber, Latin for red. Ruby is considered one of the four precious stones, together with sapphire, emerald and diamond. It has a hardness level of 9.

Ruby is the birthstone for July and the gem for the 15th and 40th anniversaries.

Source: GIA

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