The Compendium of Caraka 6.1.3.5

6.1.3.5

rūpyasya kaṭukaḥ śvetaḥ śītaḥ svādu vipacyate/
tāmrasya barhikaṇṭhābhastiktoṣṇaḥ pacyate kaṭu//
yastu guggulukābhāsastiktako lavaṇānvitaḥ/
kaṭurvipāke śītaśca sarvaśreṣṭhaḥ sa cāyasaḥ//
gomūtragandhayaḥ sarve sarvakarmasu yaugikāḥ/
rasāyanaprayogeṣu paścimastu viśiṣyate//
yathākramaṃ vātapitte śleṣmapitte kaphe triṣu/
viśeṣataḥ praśasyante malā hemādidhātujāḥ//
śilājatuprayogeṣu vidāhīni gurūṇi ca/
varjayet sarvakālaṃ tu &kulatthān parivarjayet//
&`kunakhān' iti pā-.
te hyatyantaviruddhatvādaśmano bhedanāḥ param/
loke dṛṣṭāstatasteṣāṃ prayogaḥ pratiṣidhyate//
payāṃsi &takrāṇi rasāḥ sayūṣāstoyaṃ samūtrā vividhāḥ kaṣāyāḥ/
āloḍanārthaṃ girijasya śastāste te prayojyāḥ prasamīkṣya kāryam//
&`śuktāni' iti pā.
na so 'asti rogo bhuvi sādhyarūpaḥ śilāhvayaṃ yaṃ na jayet prasahya/
tat kālayogairvidhibhiḥ prayuktaṃ svasthasya corjāṃ vipulāṃ dadāti//

That of silver is pungent, white, cool, and digests sweet.
That of copper resembles a peacock's neck, is bitter, hot, and digests pungent.
That, however, which looks like guggulu, is bitter with salt,
pungent in post-digestive effect, and cool, is from iron, and is the best of all.
All have the smell of cow urine and are suited for all procedures,
but for the administration of rejuvenatives, the last is superior.
In vāta-pitta, śleṣma-pitta, kapha, and in all three respectively,
the excretions arising from the minerals gold and the like are particularly praised.
During regimens of śilājatu, one must avoid foods causing burning and heavy foods;
at all times, however, one must completely avoid horsegram.
For they, being exceedingly incompatible, are observed in the world
to be the foremost splitters of stone; therefore, their use is prohibited.
Milk, buttermilk, meat soups, pulses, water, urine, and various decoctions
are commended for stirring śilājatu; they should be used after examining the purpose.
There is no curable disease on earth which that called stone cannot forcefully conquer;
administered according to rule at appropriate times, it also grants abundant energy to the healthy.