Most people imagine an ideal red when they think of “ruby red”, like R11756 on the right. It is bright, saturated, and vivid, but only represents a very small range of possible ruby colors. Very few rubies reach this ideal color too, with the most having a modifying color like purple to make a purplish red. Orange modifiers are usually less desirable in rubies than the purple ones.
None of these rubies have color like R11756 between issues with modifying colors and highly compromised cuts, but they meet the requirements to be a ruby. A ruby does not have to be transparent to qualify either, the only requirement is color. You can have an opaque ruby crystal and so long as red is the dominant color, the stone is a ruby.
A note about the ruby crystal R2005 above is that it has grown in a sapphire habit (the other variety of corundum) of a tall, six-sided spindle shape. This is most likely due to the opaque nature of the crystal since transparent, facet-grade rubies usually grow in a flat, six-sided, tabular shape that is largely responsible for shallow-cut in examples like R12059 and R12250 above.