In the Chamber of Secrets.

Yang Xuan sat on the ground, holding the colorless stone in his hand, his face was calm, and he seemed to be unfazed, but at this moment, his heart was already turbulent.

Under the detection of his mind, he found that this transparent stone the size of a baby's fist actually contained a huge amount of spiritual energy, and the density was incomparable.

A large amount of aura has gathered, and it has been transformed from a gaseous state to a liquid state, and drop by drop of aura is transparent and crystalline, exuding a beautiful brilliance.

Hundreds of millions of drops or even more of the liquid aura formed a vast ocean, setting off monstrous waves from time to time.

The surprise in Yang Xuan's heart was indescribable.

Because he found that these auras could be absorbed by him.

In the treasure house, he inadvertently absorbed a trace of one of the spiritual energy, which actually made the six cyclones in his body grow stronger, which shows how amazing the spiritual energy content in this stone is.

Suppressing the ecstasy in his heart, Yang Xuan calmed down his mind, used his mind as a bridge, and began to cultivate.

The next moment, a huge amount of spiritual energy surged, pouring out of the stone, and frantically poured into his body, pouring into the six cyclones.

Relax and feel good!

For a while, Yang Xuan felt like a tired traveler who had soaked in a hot spring, and it was like a long-drought earth that ushered in a nectar and regained its vitality.

The feeling of comfort, indescribable, made him almost moan.

The aura poured in, and the cyclone grew at a speed visible to the naked eye.

One, two, three......

Time passed slowly, sunrise, sunset! Yang Xuan was completely immersed in cultivation, not asking about foreign affairs.

In this way, Yang Xuan sat in this secret room for thirteen days, and the six huge cyclones in his body were finally saturated, and he automatically stopped absorbing the spiritual energy in the stone.

In the void, the golden lightning reappeared without accident.

Yang Xuan was ecstatic, after a short time, he actually broke through again, all of this was the effect of the colorless transparent stone.

Seven golden dragons danced wildly, mighty, and roared and rushed towards Yang Xuan.

The energy of destroying the heavens and the earth overflowed, just like the destruction and rebirth of the Xuan Universe.

"Boom!", after experiencing the test of the golden lightning dragon again, the cyclone in Yang Xuan's dantian suddenly exploded, and seven brand-new cyclones appeared in Yang Xuan's dantian.

Seven layers of qi refining!

Not long after, he broke through again!

Yang Xuan opened his eyes, and the essence was shining, like a sharp long sword, piercing the space.

Feeling a huge and incomparable power filling his body, a slight fist, the strong wind overflowed, as if even the space could be crushed, and between the gestures, it was full of great power.

"Come out!" Yang Xuan drank lightly.

As Yang Xuan stopped drinking, he saw a fire dragon about a zhang long appear behind him out of thin air, opening its teeth and dancing its claws, exuding boundless power and heat.

"Fire Dragon Technique!" Yang Xuan spat out a name.

"Ang!" The fire dragon raised its head to the sky and roared, and the huge sound passed through the secret room, scattering in all directions, and the power soared to the sky, and the birds and beasts around it trembled, kneeling on the ground, not daring to move.

Hahahaha, Yang Xuan laughed.

When he refined the seventh layer of qi, he had a new understanding of the use of aura.

This fire dragon is his new use of fire, with boundless flames, forming a fire dragon, making the power of flames more condensed, and has the power to incinerate all things.

Previously, although his flames were powerful, they dispersed but not condensed, and the range was too huge, invisibly dispersing the power of the flames, but now, he formed the flames into a fire dragon, just like forming a sharp blade of the golden aura, making the power more concentrated and condensed.

Moreover, this formed fire dragon is completely controlled by his mind, it can be large or small, extremely flexible, varied, and powerful.

As soon as his mind moved, the fire dragon flew around Yang Xuan's body, making Yang Xuan look like a god, and his power was amazing.

After playing for a while, Yang Xuan's mind moved again, and the fire dragon turned into a little firelight, disappeared into the air, and disappeared completely.

Yang Xuan felt the changes in his body and felt full of strength.

When he was refining the fifth layer of qi, in terms of strength, he was already on par with the peak of the eighth layer of internal strength, and the sixth layer was equivalent to the peak of the ninth layer of the martial artist, and now, seven cyclones had been formed in his body, and I am afraid that it was not much different from the peak of the tenth layer of internal strength.

But he didn't really fight with the master of the tenth layer of internal strength, and Yang Xuan just guessed like this.

However, with his powerful Dao Technique, he would never be afraid of anyone.

That's power!

When his strength reaches a certain level, his heart becomes stronger.

Then, he looked at the colorless stone in his hand and fell into deep thought.

After thirteen days of absorption, this colorless transparent stone obviously felt much smaller, thinking that it was because Yang Xuan had absorbed a large amount of spiritual energy.

However, what Yang Xuan cared about was, what exactly was this transparent stone, and why did it contain such a huge reserve of spiritual energy?

With such questions, after he got out of the customs, he came to the family library.

After showing the token, he entered the library without any hindrance, and under the eager and awe-inspiring gazes of several guards.

In the huge space, rows of bookshelves are neatly arranged, and countless books are neatly placed on each shelf.

According to rough estimates, there are no less than hundreds of thousands of books in the entire library cabinet.

This is a collection of hundreds of years by a family, and it can never be achieved overnight.

Yang Xuan looked carefully, and saw that there were labels on each shelf, which were classified and uniform, and it was very convenient to find.

Among them, there are books on martial arts, martial arts, and the cultivation experience of predecessors, as well as mainland history, biographies of celebrities, anecdotes, and so on.

These are not Yang Xuan's goals, especially those martial arts and exercises, in the eyes of others, they are extremely precious, but for Yang Xuan, it is not worth mentioning.

For these books, Yang Xuan walked by, didn't even look at them, and went straight to his goal.

It was a huge bookshelf, covered with dust, and it could be seen that no one had read the books on it for a long time, and there was a label on the top of the bookshelf with three big words on it.

Yang Xuan looked carefully, and there were many books on the shelves, all of which were books introducing various minerals. Yang Xuanxin pulled out a copy.

The title of the book is "The Geography of the Yan Kingdom".

When I opened it, it was a book about the geography of Yan Kingdom, which explained where there were minerals and what the reserves were, and the details were specific.

Yang Xuan put the book back on the shelf, and took out another copy, but it was "Copper Mine Smelting".

Yang Xuan smoked several books in a row, all of which were books on minerals, and in desperation, he had to calm down and check them one by one.

That's a lot of days.

Fortunately, Yang Qingshan had already ordered that there was no limit to the time Yang Xuan could enter the Library Pavilion, and there were still people delivering food every day, so there was no need to go out to eat.

However, in this short period of time, he had read a great deal of books, and he had read a lot of books on minerals, but none of them mentioned the transparent stone.

At this time, he was holding a copy of the "Mineral Overview" in his hand.

With his cultivation at this time, even if it is ten lines at a glance, it is not enough to describe the speed at which he reads, and in the time of the rattling of the pages, more than a dozen pages have already been turned.

Moreover, he has a clear head and eyes and never forgets, and this knowledge has been turned into small points of light and stored in his brain.

"Well, smelting zinc ore and plating it on the surface of iron can make iron stainless for a hundred years! Isn't this galvanizing technology?" Yang Xuan said to himself.

Coming from Earth, he didn't know much about it, but he had heard of some terms.

For example, the galvanizing technology mentioned in the book he is reading now has already been applied on a large scale on the earth in his previous life, so how can he not know.

Through this period of reading, he has broadened his horizons, but for the colorless transparent stone, there is still no progress.

After turning this book, he took out another book, and when he saw it, it turned out to be a book of "Heaven and Earth Different Fire Collection", but it talked about several rare flames between heaven and earth.

After turning it over, there was still nothing, Yang Xuan frowned and was silent, still patient, and wanted to check the next book, which is also due to his character, if he sees a goal, he will never change.

Suddenly, due to the slight shaking of the bookshelf, a book actually fell from the top of the bookshelf, dusty all over, and even spiders crawled over, it looked really shabby.

Yang Xuan picked it up and patted the dust on it, wanting to see what kind of book it was, but found that there was no name at all. opened it and took a look, but it turned out to be a disciple of unknown generation, writing a prospecting diary and experience.

Yang Xuan flipped through it casually, and suddenly, a record came into his eyes.

"Today, I went deep into an unnamed cave in the Milian Valley, and I didn't find any trace of the dark feather iron mine, but I found a colorless transparent stone, which was very beautiful, so I took out two pieces and kept them as a souvenir!"

Yang Xuan was overjoyed, he finally found a record about this stone.

Surprised, he hurriedly continued to watch.

But for a long time after that, this unknown predecessor recorded that he was looking for various minerals, but he did not mention the transparent stone.

Fortunately, this diary is very thick, although the record is messy, but it is also very detailed, and it took a long time before Yang Xuan found a record of the transparent stone.

"Sorting out the ore, I found that there were two colorless transparent stones, so I conducted research, first checked the records of my ancestors, and found nothing. Then I studied it carefully, and found that there was no metal in it, and it seemed to be a useless stone, but this stone was transparent and clear, so it was better to take it back and play with Feng'er, so I put it in the box!"

Yang Xuan flipped through the diary again, and until the whole diary was finished, he didn't find even the slightest record of this stone.

It seems that this kind of stone is not known to outsiders at all.

It is not surprising that the world is so big that no one dares to say that they must know everything in the world.

Although he didn't figure out what this stone was, Yang Xuan was still overjoyed in his heart, because he got a more important piece of news from it, that is, the Milian Valley.

According to the records of this ancestor disciple, there were a large number of such stones in an unnamed cave called the Valley of Miren.

Where is Milian Valley?

Yang Xuan went straight to the mainland geographical library area.