Rubys are a variety of Gems can be found in Meteorite crashes that occur once every 20 to 45 minutes It can be obtained by killing Ruby Scarabs.

You can also obtain rubys from mounds.

Rubys are required to created Golden Ruby Equipment, which can be made at Smithing Level 40.

Required to obtain:

Level	Equipment	Bars required	XP for forging	Sells for
35	Ruby Necklace	4x Ruby 4x Silver Bar	4,080	270
40	Ring of Treasure	1x Gold Bar 1x Ruby 1x Sapphire 1x Arosite	20,000	280,000
40	Ruby Sword	3x Gold Bar 3x Ruby	60,000	264,000
40	Ruby Platebody	5x Gold Bar 2x Ruby	100,000	416,000
40	Ruby Helm	8x Gold Bar 4x Ruby	80,000	680,000
50	Battle Necklace	4x Gold Bar 4x Ruby 4x Arosite 4x Magnetite 4x Emerald	45,000	270