Opals3049 are at once very similar to, and very different from, beryls, and only yield to the smaragdus in value. India, too, is the sole3050 parent of these precious stones, thus completing her glory as being the great producer of the most costly gems. Of all precious stones, it is opal that presents the greatest difficulties of description, it displaying at once the piercing fire of carbunculus,3051 the purple brilliancy of amethystos, and the sea-green of smaragdus, the whole blended together and refulgent with a brightness that is quite incredible. Some authors have compared the effect of its refulgence to that of the colour known as Armenian3052 pigment, while others speak of it as resembling the flame of burning sulphur, or of flame fed with oil. In size, the opal is about as large as a hazel-nut,3053 and, with reference to it, there is a remarkable historical anecdote related. For there is still in existence a stone of this class, on account of which Antonius proscribed the senator Nonius, son of the Nonius Struma, whom the poet Catullus3054 was so displeased at seeing in the curule chair, and grandfather of the Servilius Nonianus, who in our own times was consul.3055 On being thus proscribed, Nonius took to flight, carrying with him, out of all his wealth, nothing but this ring, the value of which, it is well known, was estimated at two millions of sesterces. How marvellous must have been the cruelty, how marvellous the luxurious passion of Antonius, thus to proscribe a man for the possession of a jewel! and no less marvellous must have been the obstinacy of Nonius, who could thus dote upon what had been the cause of his proscription; for we see the very brutes even tear off the portion of their body for the sake of which they know their existence to be imperilled,3056 and so redeem themselves by parting with it.