From BiblePortal Wikipedia

King James Dictionary [1]

RU'BY, n. L. rubeo, to be red.

1. A precious stone a mineral of a carmine red color, sometimes verging to violet, or intermediate between carmine and hyacinth red but its parts vary in color, and hence it is called sapphire ruby or orange red, and by some vermeille or rubicel.

There are two kinds of ruby, the oriental or corundum, and the spinelle. The latter is distinguishable from the former by its color and crystallization.

The ruby is next in hardness and value to the diamond, and highly esteemed in jewelry.

2. Redness red color. 3. Any thing red. 4. A blain a blotch a carbuncle. The ruby is said to be the stone called by Pliny a carbuncle.

Ruby of arsenic or sulphur, is the realgar, or red combination of arsenic and sulphur.

Ruby of zink, is the red blend.

Rock ruby, the amethystizontes of the ancients, is the most value species of garnet.

RU'BY, To make red.

RU'BY, a. Of the color of the ruby red as ruby lips.

Webster's Dictionary [2]

(1): ( a.) Ruby-colored; red; as, ruby lips.

(2): ( n.) See Agate, n., 2.

(3): ( n.) That which has the color of the ruby, as red wine. Hence, a red blain or carbuncle.

(4): ( n.) The color of a ruby; carmine red; a red tint.

(5): ( n.) A precious stone of a carmine red color, sometimes verging to violet, or intermediate between carmine and hyacinth red. It is a red crystallized variety of corundum.

(6): ( v. t.) To make red; to redden.

(7): ( n.) Any species of South American humming birds of the genus Clytolaema. The males have a ruby-colored throat or breast.

American Tract Society Bible Dictionary [3]

The oriental ruby is next in value, as a gem, to the diamond. Indeed, a ruby of this kind, above a certain size, is more valuable than a diamond of the same weight. The oriental ruby is a red variety of the sapphire its color is usually between a vivid cochineal and crimson. The word "rubies" occurs several times in the English Bible, as  Job 28:18;  Proverbs 3:15;  8:11; but the corresponding word in Hebrew is thought to denote red coral, or perhaps pearls; while the true ruby is more naturally designated by the "agate" or "carbuncle" of  Isaiah 54:12;  Ezekiel 27:16 .

Watson's Biblical & Theological Dictionary [4]

a beautiful gem, whose colour is red, with an admixture of purple, and is, in its most perfect state, a gem of extreme value. In hardness it is equal to the sapphire, and second only to the diamond. It is mentioned in  Job 28:18 , and  Proverbs 8:11 , &c.

Easton's Bible Dictionary [5]

 Lamentations 4:7 Exodus 28:17 Job 28:18 Proverbs 3:15 8:11 Proverbs 31:10

Holman Bible Dictionary [6]

Minerals And Metals

Hastings' Dictionary of the Bible [7]

RUBY . See Jewels and Precious Stones.

Cyclopedia of Biblical, Theological and Ecclesiastical Literature [8]

(only plur. פְּנַינַי ם Peninim ; once [Proverbs 315, Kethib] פְּנַיַּי ם , Peniyim ; Sept. Λίθοι , or Λίθοι Πολυτελεῖς ; Vulg. Cunctoe Opes , Cuncta Pretiosissima , Gemmoe , De Ultimis Finibus , Ebor Antiquum ), a gem concerning which there is much difference of opinion and great uncertainty. It occurs in the following passages: "The price of wisdom is above peninim" ( Job 28:18; so also  Proverbs 3:15;  Proverbs 8:11;  Proverbs 31:10); "A multitude of Peninim " (20:15). In  Lamentations 4:7, it is said, "the Nazarites were purer than snow, they were whiter than milk, they were more ruddy in body than Peninim. " Boote ( Animad. Sac. 4, 3), on account of the ruddiness mentioned in the last passage, supposed "coral" to be intended, for which, however, there appears to be another Hebrew word. (See Coral). Michaelis ( Suppl. p. 2023) is of the same opinion, and compares the Heb. פְּנַנָּה ; with the Arab. Panah , "a branch." Gesenius (Thesaur. s.v.) defends this argument. Bochart (Hieroz. 3, 601) contends that the Hebrew term denotes pearls, and explains the "ruddiness" alluded to above by supposing that the original word ( אָדְמוּ ) signifies merely "bright in color," or "color of a reddish tinge." This opinion is supported by Rosenm Ü ller ( Schol. In Thren. ) and others, but opposed by Maurer ( Comment. ) and Gesenius. Certainly it would be no compliment to the great people of the land to say that their bodies were as red as coral or rubies, unless we adopt Maurer's explanation, who refers the "ruddiness" to the blood which flowed in their veins. (See Ruddy). On the whole, considering that the Hebrew word is always used in the plural, we are inclined to adopt Bochart's explanation, and understand pearls to be intended. (See Pearl).

The ruby is, however, generally supposed to be represented by the word כּ דְכֹּד , Kad-Kod ', which occurs in  Ezekiel 27:6, and  Isaiah 54:12, where the A.V. renders it "agate" (q.v.). An Arabic word of similar sound ( Kadskadsat ) signifies "vivid redness;" and as the Hebrew word may be derived from a root of like signification, it is inferred that it denotes the Oriental ruby, which is distinguished for its vivid red color, and was regarded as the most valuable of precious stones next after the diamond. This mode of identification, however, seems rather precarious. The Greek translator of  Ezekiel 27:16 does not appear to have known what it meant, for he preserves the original word; and although the translator of  Isaiah 54:12 has Jasper (Gr. Iaspis , Ἴασπις ), he is not regarded as any authority in such matters when he stands alone. The ruby was doubtless known to the Hebrews, but it is by no means certain that Kad - Kod was its name. Some have supposed that the word Ekdach , אֶקְדָּח , which from its etymology should signify a sparkling, flaming gem, is to be regarded as a species of ruby. It occurs only in  Isaiah 54:12; hence the Sept. and A.V. make it a "carbuncle" (q.v.).

The ruby of mineralogists is a red sapphire (q.v.) or spinel. It is a gem highly prized, and only inferior in value to the diamond. The finest are the Oriental, which are chiefly brought from Ceylon and Burmah. They are found in alluvial deposits. The ruby, like other gems, had a host of occult virtues attributed to it by the Cabalists. It was supposed to give valor to the soldier in battle; to decide and concentrate affection; to foretell evil by growing pale, and to indicate that the danger was past by recovering its vivid color. (See Gem).

The Nuttall Encyclopedia [9]

A gem which in value and hardness ranks next to the diamond; is dichroic, of greater specific gravity than any other gem, and belongs to the hexagonal system of crystals; is a pellucid, ruddy-tinted stone, and, like the sapphire, a variety of corundum, also found (but rarely) in violet, pink, and purple tints; the finest specimens come from Upper Burmah; these are the true Oriental rubies, and when above 5 carats exceed in value, weight for weight, diamonds; the Spinel ruby is the commoner jeweller's stone; is of much less value, specific gravity and hardness, non-dichroic, and forms a cubical crystal.

Kitto's Popular Cyclopedia of Biblial Literature [10]

The word rendered 'ruby' in the Authorized Version (;;;;; ) appears rather to indicate 'pearls.' The ruby is, however, generally supposed to be represented by the word rendered 'agate' in , and . The Oriental ruby is distinguished for its vivid red color, and was regarded as the most valuable of precious stones next after the diamond.