The Agni Purāṇa recommends thirty-six gemstones for activation of rājayoga for the kings. I guess ordinary mortals can also make good use of these recommendations. The Sanskrit recommendation and our translation is given below.

वज्रं मरकतं रत्नं पद्मरागं च मोक्तिकम्॥
vajraṁ marakataṁ ratnaṁ padmarāgaṁ ca mouktikam||
(1) Diamond (2) Emerald (3) Ruby (4) Pearl

इन्द्रनीलं महानीलं वैदूर्यं गन्धशस्यकम्।
indranīlaṁ mahānīlaṁ vaidūryaṁ gandhaśasyakam|
(5) Aquamarine (6) Blue Sapphire (7) Vaidūrya [Scapolite?]

चन्द्राकान्तं सूर्यकान्तं स्फटिकं पुलकं तथा॥
candrākāntaṁ sūryakāntaṁ sphaṭikaṁ pulakaṁ tathā||
(8) Moonstone (9) Sunstone (10) Sapphire Crystal (11) Pulaka [green tourmaline]

कर्केतनं पुष्परागं तथा ज्योतिरसं द्विज।
karketanaṁ puṣparāgaṁ tathā jyotirasaṁ dvija|
(12) Quartz (13) Yellow Sapphire (14) star-gems [star-ruby etc.]

स्फटिकं राजपट्टं च तथा राजमयं शुभम्॥
sphaṭikaṁ rājapaṭṭaṁ ca tathā rājamayaṁ śubham||
(15) Sapphire Crystal (16) rājapaṭṭa [natural diamond] (17) rājamaya

सौगन्धिकं तथा गञ्जं सङ्खब्रह्ममयं तथा।
saugandhikaṁ tathā gañjaṁ saṅkhabrahmamayaṁ tathā|
(18) Sulphur [Golden Topaz] (19) gañja (20) Conch-Shell

गोमेदं रुधिराक्षं च तथा भल्लातकं द्विज॥
gomedaṁ rudhirākṣaṁ ca tathā bhallātakaṁ dvija||
(21) Gomeda [Dolomite, Hessonite – 4 sorts , white , pale yellow , red , and dark blue] (22) rudhirākṣa [like rudrākṣa -] (23) Marking-nut [Rhodolite Garnet or similar reddish gemstone]

धूलिं मरकतं चैव तुत्थकं सीसमेव च।
dhūliṁ marakataṁ caiva tutthakaṁ sīsameva ca|
(24) copper nitrate (25) Emerald (26) Blue vitriol (27) lead

पीलुं प्रवालकं चैव गिरिवज्रं द्विजोत्तम॥
pīluṁ pravālakaṁ caiva girivajraṁ dvijottama||
(28) Ivory (29) Coral (30) mountain-diamond ?

भुजङ्गमणिं चैव तथा वज्रमणिं शुभं।
bhujaṅgamaṇiṁ caiva tathā vajramaṇiṁ śubhaṁ|
(31) nāga-maṇi [snake-gem] (32) diamond-like gemstone

टिट्टिभं च तथा पिण्डं ब्रामरं च तथोत्पलम्॥
ṭiṭṭibhaṁ ca tathā piṇḍaṁ brāmaraṁ ca tathotpalam||
(33) Rhodochrosite (34) Pyrite (35) Black onyx [black pearl] (36) Amethyst

Vaidūrya Correction

It is very interesting to note that ‘vaidūrya’ which was suspected to be cat’s eye gemstone by astrologers for such a long time seems to be quite different. Vedavyāsa specifically uses the word ‘nīla-rakta’ indicating that it is bluish-red in colour. Cat’s-Eye is a feature that can apply to many gemstones including Cat’s Eye Apatite, Cat’s Eye Aquamarine, Cat’s Eye Diaspore, Cat’s Eye Scapolite, Cat’s Eye Tourmaline. Cat’s-Eye simply means a line of light that tilts with the stone. Don’t get carried away with that. What we are looking for is a gemstone which has the blue and red colours blended together.

Application

These thirty-six gemstones are recommended based on the 36 drekkāṇa. For many thousand years the Indians, Persians and the Egyptians have used the drekkāṇa for timing political events and it is evident that this recommendation could be on these lines.