1.Nav-Nidhi of Kubera as mines, minerals, earthenware and ocean resources

The semantics provided in parenthesis will be explained further in the following sections. The categories involved in the nine treasures of Kubera are: minerals worked on to produce metals and alloys and related artefacts, mineral sources (Padma, Mahapadma), products of smiths (baked vessels), products of the sea traded (tortoise or turtle shell or conch shell). In the case of the conch shell, s’ankha, the basic source of wealth is also worked on to produce wide and red-pigmented bangles, to make trumpets (conches) and polished, painted on the edges in red to be used as sacred ladles for libations or for feeding medicines or milk to infants.

Such are the Navanidhi of Kubera or the nine treasures of Hindu civilization.

The eight directions are decorated with the eight jewels of Mahapadma, Padma, Sankha, Makara, Kacchapa, Mukunda, Kunda, and Nila. (Brahma Samhita: astabhir nidhibhir justam is explained as these eight jewels.) http://www.bvml.org/SBS/1.html

1.1 Padma and   1.2. Mahapadma (mines)
Padma and Mahapadma are references to two lakes on Himalayan mountains which are rich in minerals. Tatvartha Sutra notes: Manivichitraparshva upari mule cha tulya-vistarah (Trans.Those mountains are of equal width at the foot, in the middle and at the top, and their sides are studded with various jewels.)
Hence, Padma and Mahapadma are two of the Navanidhi of Kubera studded with minerals and jewels.

Nilamata Purana refers to a lake called Mahapadma lake controlled by a Naga. “And that Mahapadma lake, one Yojana long and one Yojana wide, is heavenly, beautiful and pleasing to the hearts of the good. Due to the influence of Mahapadma, (that lake is) devoid of wicked crocodiles. The Naga, surrounded by his family, lives there happily. ” (Nilamata Purana, 1022-23).

Padma, Mahapadma, Tiginchha, Kesari, Mahapundarika and Pundarika respectively are the lakes on the top of these mountains.
Prathamo yojanasahastraya-masta- darddhavishkambho hradah
_Padma, the first lake is 1,000 yojanas in length and 500 yojana in breadth.
Dashayojanavagahah
_Depth of the first lake is ten yojans.
_In the middle of this first lake, there is a lotus of the size of one yojana.
Size of Mahapadma lake and the lotus in it is double that of Padma lake. Similarly, the size of Tiginchha lake and the lotus is double that of Mahapadma lake. Kesri, Mahapundrika and Pundrika are similar to Tiginchha, Mahapadma and Padma respectively.

1.3 Makara: synonym Padmini, Kohl, Anjana, black antimony

“Lupus metallorum = The grey wolf or stibnite, used to purify gold, as the sulphur in the antimony sulphide bonds to the metals alloyed with the gold, and these form a slag which can be removed. The gold remains dissolved in the metallic antimony which can be boiled off to leave the purified gold.”
While ni_la could be antimony, padmini (makara) could be ni_la_njana or black arsenic, an unguent made of antimony and blue vitriol. Antimony is said to be produced in the river Yamuna (srotonjana or ya_muna mentioned in the Atharva Veda, as a reference to antimony or collyrium). the black sulphide of antimony,Sb2S3, used in pyrotechnics. Antimony black is antimony trisulfide or stibnite ore; antimony bloom is antimony trioxide. Antimony trioxide is produced from stibnite or as a by-product of lead smelting and production.

Makara is half animal half fish. For example, he is sometimes described as having the head of an elephant and the body of a fish. Makara is one of the 8 magical treasures called Padmini, according to Markandeya Purana.

1.4 Ni_la, antimony

Antimonial bronze, Arsenical bronze, Lead bronze, Brass
Neela = blue sapphire (Skt.); ni_la man.i = sapphire gemstone . “The introduction of antimony in addition to the tin and copper produces a harder bronze, better able to hold a cutting edge and less likely to be bent in use. Like antimony, arsenic added to the tin and copper (up to as much as 3% of the whole) produces a harder final product… Mixing lead into the copper-tin alloy produces “lead bronze,” which may contain as much as 10% lead.

The lead in the alloy does not become part of its crystalline structure, increasing the fluidity of compound when it is in its molten state. This facilitates casting, particularly the casting of finely detailed artistic objects… Brass is an alloy of copper with zinc, and is usually made up of anywhere from ten to forty percent zinc.”

1.5 Mukunda, mercuric sulphide or cinnabar, sindhur(refined to produce quicksilver)
Quicksilver fuses at all ordinary temperatures, eating and absorbing gold and silver metals until they form a soft pasty mass. The application of a red heat expels the quicksilver, leaving the metal nearly pure.
mukunda quicksilver; a kind of precious stone; name of one of the nine treasures of Kubera

“Mercury, called quicksilver by the ancients, is a liquid metal that could be found weeping through cracks in certain rocks or accumulating in small puddles in mountain grottos. It was also obtained by roasting cinnabar (mercury sulfide). The shiny metal would seep from the rocks and drip down into the ashes, from which it was later collected. The early alchemists made red mercuric oxide by heating quicksilver in a solution of nitric acid. The acid, which later alchemists called “aqua fortis,” was made by pouring sulfuric acid over saltpeter.”

1.6 Kunda, arsenic (to produce bell-metal)

kuntam a mineral poison, kar-pa_s.a_n.am, ta_lam-pa_s.a_n.am; a standard weight = 4 palam; one of the nine treasures of Kuber.

Thus, kunda refers to ‘arsenic’ and mukunda refers to ‘quick silver’.
kundan = pure gold (G.Persian); the socket of a gem (G.) kundanamu = fine gold used in very thin foils in setting precious stones

1.7 Kharva, baked cup

kharva = cup baked in fire (TS.) {one of Kubera’s nine treasures, nava-nidhi} rebus: karavai = a tool of a blacksmith (Ta. katirve_rpil.l.ai. lex.); karava_yi, kharavayi_ = an instrument of braziers; an anvil or curved metallic bar on which vessels are hung to be hammered (M.Ka.Te.) karava = clay pot with narrow neck (Kod.)

1.9 S’ankha, conch

Krsna’s conch-shell was named ‘Panchajanya’, Arjun’s ‘Devadatta’, Bhim’s ‘Paundra’. Yudhisthir’s ‘Ananta-vijaya’, Nakul’s ‘Sughosha’ amd Sahadeva’s “Mani-pushpaka’ (Bhagavadgita1:15-16).
Vis.n.u holds the valampuri conch or right-spiralled conch which is an object of veneration among the Hindu-s.
Conch or Sankha in Hinduism is regarded as a very special ornament/treasure to possess. Just by blowing it, not only keeps the evil spirit away from the home/temple/place where it is kept and utilised but also clears many confused minds and bodies.

Worshipping both Lakshmi and Vishnu sankhs together also ensures that the household will never be short of wealth of treasure, money, happiness, peacefulness and contentment

1.8 Kacchapa, tortoise or turtle shell

ku_rma, kamat.ha, kacchapa tortoise (Skt.) If kacchapa refers to the synonym, kamat.ha, there could be a rebus explanation for kamat.ha as a nidhi of Kubera. Rebus, kampat.t.a means a mint, smithy. An alternative is to assume that kacchapa, turtle itself or tortoise shell was a traded commodity. The so-called Periplus of the Erythraean Sea describes the trade in detail. At the time this text was written (late first century AD) India was importing copper, tin, and lead. Her exports included such items as ivory, agate, carnelian, pearls and tortoise shell, many of which are familiar as items associated with the Meluhha trade…